Acid-free quaternized nitrogen compounds and use thereof as additives in fuels and lubricants

ABSTRACT

The present invention relates to novel acid-free quaternized nitrogen compounds, to the preparation thereof and to the use thereof as a fuel and lubricant additive, more particularly as a detergent additive, as a wax antisettling additive (WASA) or as an additive for reducing internal diesel injector deposits (IDID); to additive packages which comprise these compounds; and to fuels and lubricants thus additized. The present invention further relates to the use of these acid-free quaternized nitrogen compounds as a fuel additive for reducing or preventing deposits in the injection systems of direct-injection diesel engines, especially in common-rail injection systems, for reducing the fuel consumption of direct-injection diesel engines, especially of diesel engines with common-rail injection systems, and for minimizing power loss in direct-injection diesel engines, especially in diesel engines with common-rail injection systems.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of prior U.S. applicationSer. No. 15/423,240, filed Feb. 2, 2017, issued as U.S. Pat. No9,988,589, the disclosure of which is incorporated by reference in itsentirety. U.S. application Ser. No. 15/423,240 is a continuation of U.S.application Ser. No. 14/724,404, filed May 28, 2015, the disclosure ofwhich is incorporated by reference in its entirety. U.S. applicationSer. No. 14/724,404 is a continuation of U.S. application Ser. No.14/337,307, filed Jul. 22, 2014, issued as U.S. Pat. No 9,255,235 onFeb. 9, 2016, the disclosure of which is incorporated by reference inits entirety. U.S. application Ser. No. 14/337,307 is a divisionalapplication of U.S. application Ser. No. 13/177,042, filed Jun. 7. 2011,now abandoned, the disclosure of which is incorporated by reference inits entirety. U.S. application Ser. No. 13/177,042 claims priority toU.S. patent application No. 61/485,196, filed May 12, 2011, and U.S.application Ser. No. 61/361,572, filed Jul. 6, 2010, the disclosures ofwhich are incorporated herein by reference in their entireties.

The present invention relates to novel acid-free quaternized nitrogencompounds, to the preparation thereof and to the use thereof as a fueland lubricant additive, more particularly as a detergent additive, as awax antisettling additive (WASA) or as an additive for reducing internaldiesel injector deposits (IDID); to additive packages which comprisethese compounds; and to fuels and lubricants thus additized. The presentinvention further relates to the use of these acid-free quaternizednitrogen compounds as a fuel additive for reducing or preventingdeposits in the injection systems of direct-injection diesel engines,especially in common-rail injection systems, for reducing the fuelconsumption of direct-injection diesel engines, especially of dieselengines with common-rail injection systems, and for minimizing powerloss in direct-injection diesel engines, especially in diesel engineswith common-rail injection systems.

STATE OF THE ART

In direct-injection diesel engines, the fuel is injected and distributedultrafinely (nebulized) by a multihole injection nozzle which reachesdirectly into the combustion chamber in the engine, instead of beingintroduced into a prechamber or swirl chamber as in the case of theconventional (chamber) diesel engine. The advantage of thedirect-injection diesel engines lies in their high performance fordiesel engines and nevertheless low fuel consumption. Moreover, theseengines achieve a very high torque even at low speeds.

At present, essentially three methods are being used to inject the fueldirectly into the combustion chamber of the diesel engine: theconventional distributor injection pump, the pump-nozzle system(unit-injector system or unit-pump system) and the common-rail system.

In the common-rail system, the diesel fuel is conveyed by a pump withpressures up to 2000 bar into a high-pressure line, the common rail.Proceeding from the common rail, branch lines run to the differentinjectors which inject the fuel directly into the combustion chamber.The full pressure is always applied to the common rail, which enablesmultiple injection or a specific injection form. In the other injectionsystems, in contrast, only smaller variation in the injection ispossible. The injection in the common rail is divided essentially intothree groups: (1.) pre-injection, by which essentially softer combustionis achieved, such that harsh combustion noises (“nailing”) are reducedand the engine seems to run quietly; (2.) main injection, which isresponsible especially for a good torque profile; and (3.)post-injection, which especially ensures a low NO_(x) value. In thispost-injection, the fuel is generally not combusted, but insteadevaporated by residual heat in the cylinder. The exhaust gas/fuelmixture formed is transported to the exhaust gas system, where the fuel,in the presence of suitable catalysts, acts as a reducing agent for thenitrogen oxides NO_(x).

The variable, cylinder-individual injection in the common-rail injectionsystem can positively influence the pollutant emission of the engine,for example the emission of nitrogen oxides (NO_(x)), carbon monoxide(CO) and especially of particulates (soot). This makes it possible, forexample, that engines equipped with common-rail injection systems canmeet the Euro 4 standard theoretically even without additionalparticulate filters.

In modern common-rail diesel engines, under particular conditions, forexample when biodiesel-containing fuels or fuels with metal impuritiessuch as zinc compounds, copper compounds, lead compounds and other metalcompounds are used, deposits can form on the injector orifices, whichadversely affect the injection performance of the fuel and hence impairthe performance of the engine, i.e. especially reduce the power, but insome cases also worsen the combustion. The formation of deposits isenhanced further by further developments in the injector construction,especially by the change in the geometry of the nozzles (narrower,conical orifices with rounded outlet). For lasting optimal functioningof engine and injectors, such deposits in the nozzle orifices must beprevented or reduced by suitable fuel additives.

WO 2006/135881 describes quaternized ammonium salts prepared bycondensation of a hydrocarbyl-substituted acylating agent and of anoxygen- or nitrogen-containing compound with a tertiary amino group, andsubsequent quaternization by means of hydrocarbyl epoxide in thepresence of stoichiometric amounts of an acid, especially acetic acid.Stoichiometric amounts of the acid are required to ensure complete ringopening of the epoxide quaternizing agent and hence very substantiallyquantitative quaternization. The reaction of a dicarboxylic acid-basedacylating agent, such as the PIBSA used in the examples therein, with anamine, such as dimethylaminopropylamine (DMAPA), under condensationconditions, i.e. elimination of water, forms a DMAPA succinimide whichis then quaternized with epoxide and acid in equimolar amounts in eachcase.

Following the technical teaching of WO 2006/135881, the presence of thestoichiometric amounts of acid, which is additionally absolutelynecessary to balance the charge for the quaternized imide detergenttherein, is found to be particularly disadvantageous. In order to reducethe acid content of the imide therein, or in order to entirely removeacid, additional process measures would be required, which would makethe preparation of the product more complex and hence would make it muchmore expensive. The epoxide-quaternized imide prepared according to WO2006/135881 is therefore—without further purification—used in the formof the carboxylate salt as a fuel additive in the tests described in theapplication.

On the other hand, however, it is known that acids can cause corrosionproblems in fuel additives (cf., for example, Sugiyama et al; SAEInternational, Technical Paper, Product Code: 2007-01-2027, DatePublished: Jul. 23, 2007). The epoxide-quaternized additive providedaccording to WO 2006/135881 is therefore afflicted with significantapplication risks a priori owing to the considerable corrosion riskwhich exists. Furthermore, the product has distinct disadvantages withregard to motor oil compatibility and low-temperature properties.

In the injection systems of modern diesel engines, deposits causesignificant performance problems. It is common knowledge that suchdeposits in the spray channels can lead to a decrease in the fuel flowand hence to power loss. Deposits at the injector tip, in contrast,impair the optimal formation of fuel spray mist and, as a result, causeworsened combustion and associated higher emissions and increased fuelconsumption. In contrast to these conventional “external” depositionphenomena, “internal” deposits (referred to collectively as internaldiesel injector deposits (IDID)) in particular parts of the injectors,such as at the nozzle needle, at the control piston, at the valvepiston, at the valve seat, in the control unit and in the guides ofthese components, also increasingly cause performance problems.Conventional additives exhibit inadequate action against these IDIDs.

It is therefore an object of the present invention to provide improvedquaternized fuel additives, especially based on hydrocarbyl-substitutedpolycarboxylic anhydrides, which no longer have the disadvantages of theprior art mentioned.

BRIEF DESCRIPTION OF THE INVENTION

It has now been found that, surprisingly, the above object is achievedby providing an addition process, performable under acid-freeconditions, for preparing epoxide-quaternized nitrogen-containingadditives based on hydrocarbyl-substituted polycarboxylic anhydrides andcompounds which have quaternizable amino groups and are reactivetherewith, and by the acid-free reaction products thus obtainable.

The inventive reaction regime surprisingly allows the addition of freeacid to be dispensed with completely, especially of free protic acidwhich, according to the prior art, necessarily has to be added to thealkylene oxide quaternizing reagent. This is because the inventiveprocess regime, by virtue of addition of the nitrogen-containingquaternizable compound onto the hydrocarbyl-substituted polycarboxylicanhydride and opening of the anhydride ring, generates anintramolecularly bound acid function, and it is assumed that, withoutbeing bound to this model consideration, that this intramolecularlygenerated carboxyl group activates the alkylene oxide in thequaternization reaction and, by protonation of the intermediate alcoholwhich forms after the addition of the alkylene oxide, forms the reactionproduct in the form of a betaine structure.

Surprisingly, the inventive additives thus prepared are superior inseveral respects to the prior art additives prepared in a conventionalmanner by epoxide/acid quaternization.

DESCRIPTION OF FIGURES

FIG. 1 shows the power loss of different diesel fuels in a DW10 enginetest. In particular, this is shown for unadditized fuel (squares) and afuel additized in accordance with the invention (rhombuses), compared toa comparative fuel admixed with prior art additive at the same dosage(triangles).

DETAILED DESCRIPTION OF THE INVENTION

A1) Specific Embodiments

The present invention relates especially to the following specificembodiments:

-   1. A process for preparing quaternized nitrogen compounds, wherein    -   a. a compound comprising at least one oxygen- or        nitrogen-containing group reactive with the anhydride, for        example an —OH and/or a primary or secondary amino group, and        additionally comprising at least one quaternizable amino group        is added onto a polycarboxylic anhydride compound, especially a        polycarboxylic anhydride or a hydrocarbyl-substituted        polycarboxylic anhydride, especially a polyalkylene-substituted        polycarboxylic anhydride, and    -   b. the product from stage a) is quaternized with an especially        H⁺ donor-free and in particular acid-free quaternizing agent.-   2. The process according to embodiment 1, wherein the polycarboxylic    anhydride compound is a di-, tri- or tetracarboxylic anhydride.-   3. The process according to either of the preceding embodiments,    wherein the polycarboxylic anhydride compound is the anhydride of a    C₄-C₁₀-dicarboxylic acid.-   4. The process according to any of the preceding embodiments,    wherein the polycarboxylic anhydride compound comprises at least one    high molecular weight hydrocarbyl substituent, especially    polyalkylene substituent, having a number-average molecular weight    (Mn) in the range from about 200 to 10 000, for example 300 to 8000,    especially 350 to 5000.    -   5. The process according to any of the preceding embodiments,        wherein the compound reactive with the anhydride is selected        from    -   a. mono- or polyamines which are substituted by low molecular        weight hydroxyhydrocarbyl, especially low molecular weight        hydroxyalkyl, and have at least one quaternizable primary,        secondary or tertiary amino group;    -   b. straight-chain or branched, cyclic, heterocyclic, aromatic or        nonaromatic polyamines having at least one primary or secondary        (anhydride-reactive) amino group and having at least one        quaternizable primary, secondary or tertiary amino group;    -   c. piperazines.-   6. The process according to embodiment 5, wherein the compound    reactive with the anhydride is selected from    -   a. primary, secondary or tertiary monoamines substituted by low        molecular weight hydroxyhydrocarbyl, especially low molecular        weight hydroxyalkyl, and hydroxyalkyl-substituted primary,        secondary or tertiary diamines,    -   b. straight-chain or branched aliphatic diamines having two        primary amino groups; di- or polyamines having at least one        primary and at least one secondary amino group; di- or        polyamines having at least one primary and at least one tertiary        amino group; aromatic carbocyclic diamines having two primary        amino groups; aromatic heterocyclic polyamines having two        primary amino groups; aromatic or nonaromatic heterocycles        having one primary and one tertiary amino group.-   7. The process according to any of the preceding embodiments,    wherein the quaternizing agent is selected from epoxides, especially    hydrocarbyl-substituted epoxides.-   8. The process according to embodiment 7, wherein the quaternization    is effected without addition of an H⁺ donor, especially without    addition of acid.-   9. The process according to any of the preceding embodiments,    wherein stage a), i.e. the addition reaction, is performed at a    temperature of less than about 80° C. and especially at a    temperature in the range from about 30 to 70° C., in particular 40    to 60° C.-   10. The process according to any of the preceding embodiments,    wherein stage a) is performed over a period of 1 minute to 10 hours    or 10 minutes to 5 hours or 10 minutes to 4 hours or 2 to 3 hours.-   11. The process according to any of the preceding embodiments,    wherein stage b), i.e. the quaternization, is performed at a    temperature in the range from 40 to 80° C.-   12. The process according to any of the preceding embodiments,    wherein stage b) is performed over a period of 1 to 10 hours.-   13. The process according to any of the preceding embodiments,    wherein stage b) is performed with an epoxide, especially low    molecular weight hydrocarbyl epoxide, as the quaternizing agent in    the absence of (stoichiometric amounts of) free acid (other than the    polycarboxylic acid compound).-   14. The process according to any of the preceding embodiments,    wherein the reaction according to stage a) and/or b) is effected in    the absence of a solvent, in particular in the absence of an organic    protic solvent.-   15. A quaternized nitrogen compound or reaction product obtainable    by a process according to any of the preceding embodiments.-   16. A quaternized nitrogen compound or reaction product according to    embodiment 15, comprising at least one compound of the general    formulae:

-   -   especially Ia-1, optionally in combination with Ia-2 and/or        Ia-3,        -   or

-   -   especially Ib-1, optionally in combination with Ib-2 and/or        Ib-3,    -   in which    -   R₁ is H or a straight-chain or branched hydrocarbyl radical        which may optionally be mono- or polysubstituted by hydroxyl,        carboxyl, hydrocarbyloxy and/or acyl radicals, or has one or        more ether groups in the hydrocarbyl chain, and is especially H        or short-chain hydrocarbyl, especially alkyl;    -   R₂ is H or alkyl; R₃ is hydrocarbyl, especially long-chain        hydrocarbyl, for example a polyalkylene radical;    -   at least one of the R₄, R₅ and R₆ radicals is a radical        introduced by quaternization, especially a low molecular weight        hydrocarbyl radical or low molecular weight hydroxyl-substituted        hydrocarbyl radical, and the remaining radicals are selected        from straight-chain or branched low molecular weight hydrocarbyl        radicals, cyclic hydrocarbyl radicals, which are optionally        mono- or polysubstituted and/or have one or more heteroatoms;    -   R₇ is H or a straight-chain or branched low molecular weight        hydrocarbyl radical which may optionally be mono- or        polysubstituted, for example di-, tri- or tetrasubstituted, by        identical or different hydroxyl, carboxyl, low molecular weight        hydrocarbyloxy and/or acyl radicals, or has one or more ether        groups in the hydrocarbyl chain, or R₇ together with one of the        R₄, R₅ and R₆ radicals forms a bridge group, for example an        alkylene or alkenylene group;    -   L₁ is a chemical bond or a straight-chain or branched alkylene        group and    -   L₂ is a straight-chain or branched alkylene group which        optionally bears one or more heteroatoms, especially selected        from —O— and —NH—, or substituents.

-   17. A quaternized nitrogen compound or reaction product according to    embodiment 15 or 16 which is essentially H⁺ donor-free, especially    essentially acid-free, and especially comprises no inorganic acids    or short-chain organic acids.

-   18. The use of a quaternized nitrogen compound or of a reaction    product according to any of embodiments 15 to 17 as a fuel additive    or lubricant additive.

-   19. The use according to embodiment 18 as a detergent additive for    diesel fuels.

-   20. The use according to embodiment 18 as a wax antisettling    additive (WASA) for middle distillate fuels, especially diesel    fuels.

-   21. The use according to embodiment 19 as an additive for reducing    or preventing deposits in injection systems of direct-injection    diesel engines, especially in common-rail injection systems, for    reducing the fuel consumption of direct-injection diesel engines,    especially of diesel engines with common-rail injection systems,    and/or for minimizing power loss in direct-injection diesel engines,    especially in diesel engines with common-rail injection systems.

-   22. The use according to embodiment 21 as an additive for    controlling (preventing or reducing, especially partly, essentially    completely or completely reducing) internal diesel engine deposits    (IDID), i.e. deposits in the interior of the injector; especially    wax or soap-like deposits and/or carbon-like polymeric deposits.

-   23. An additive concentrate comprising, in combination with further    fuel additives, especially diesel fuel additives, at least one    quaternized nitrogen compound or a reaction product according to any    of embodiments 15 and 16.

-   24. A fuel composition comprising, in a majority of a customary base    fuel, a (detergency-)effective amount of at least one quaternized    nitrogen compound or of a reaction product according to either of    embodiments 15 and 16.

-   25. A lubricant composition comprising, in a majority of a customary    lubricant, a (detergency-)effective amount of at least one    quaternized nitrogen compound or of a reaction product according to    either of embodiments 15 and 16.    A2) General Definitions

An “H⁺ donor” or “proton donor” refers to any chemical compound which iscapable of releasing a proton to a proton acceptor. Examples areespecially protic acids, but also water.

“Acid-free” in the context of the present invention means the absence oflow molecular weight inorganic or organic acid and/or of thecorresponding anion thereof, and includes both the lack of addition ofacid during the preparation process according to the invention and, moreparticularly, the absence of acid and/or of the anion thereof in thequaternized reaction product used as the additive. Freedom from acidincludes especially the absence of stoichiometric amounts of such acidsand anions thereof (stoichiometry based on the quaternizing agent used,such as especially the epoxide), and exists especially when, based onepoxide quaternizing agent used, free acid or anion thereof is presentonly in substoichiometric amounts, for example in molar ratios of lessthan 1:0.1, or less than 1:0.01 or 1:0.001, or 1:0.0001, of quaternizingagent to acid. Freedom from acid especially also includes the completeabsence of an inorganic or organic protic acid and/or anion thereof(i.e. when protic acid and/or the anion thereof is analytically nolonger detectable). An “acid” in this context is especially a freeprotic acid.

Examples of typical “protic acids” include inorganic acids or mineralacids, such as HCl, H₂SO₄, HNO₃, H₂CO₃, and organic carboxylic acids,especially monocarboxylic acids of the RCOOH type in which R is ashort-chain hydrocarbyl radical.

“Free” or “unbound” acid means that the acid function is not part of aquaternized compound itself, i.e. is in principle removable from thequaternized compound, for example by ion exchange.

Typical “anions” of protic acids are, for example, carboxylate anions,for example acetate and propionate.

“Quaternizable” nitrogen groups or amino groups include especiallyprimary, secondary and tertiary amino groups.

A “condensation” or “condensation reaction” in the context of thepresent invention describes the reaction of two molecules withelimination of a relatively small molecule, especially of a watermolecule. When such an elimination is not detectable, more particularlynot detectable in stoichiometric amounts, and the two molecules reactnevertheless, for example with addition, the reaction in question of thetwo molecules is “without condensation”.

A “betaine” refers to a specific salt form of a chemical compound whichhas both a negative charge and a positive charge in one and the samemolecule, wherein the charge, however, cannot be eliminated byintramolecular ion transfer.

“IDID” stands for “internal diesel injector deposits”, as observed inmodern diesel engines. While conventional (external) deposits arecoke-like deposits in the region of the needle tips and the spray holesof the injection nozzles, there is in the meantime an accumulation ofdeposits in the interior of the injection nozzles, which lead tosignificant performance problems, for example blockage of the internalmoving parts of the valve and associated worsening or lack of control offuel injection, power loss and the like. The IDIDs occur either in theform of wax- or soap-like deposits (fatty acid residues and/or C₁₂- orC₁₆-alkyl succinic acid residues detectable analytically) or in the formof polymeric carbon deposits. The latter in particular make particulardemands with regard to the removal/avoidance thereof.

In the absence of statements to the contrary, the following generalconditions apply:

“Hydrocarbyl” can be interpreted widely and comprises both long-chainand short-chain, straight-chain and branched hydrocarbon radicals, whichmay optionally additionally comprise heteroatoms, for example O, N, NH,S, in the chain thereof.

“Cyclic hydrocarbyl radicals” may comprise aromatic or nonaromatic ringsand optionally have one or more ring heteroatoms selected from O, S, N,NH.

“Long-chain” or “high molecular weight” hydrocarbyl radicals have anumber-average molecular weight (M_(n)) of 85 to 20 000, for example 113to 10 000, or 200 to 10 000 or 350 to 5000, for example 350 to 3000, 500to 2500, 700 to 2500, or 800 to 1500. More particularly, they are formedessentially from C₂₋₆, especially C₂₋₄, monomer units such as ethylene,propylene, n- or isobutylene or mixtures thereof, where the differentmonomers may be copolymerized in random distribution or as blocks. Suchlong-chain hydrocarbyl radicals are also referred to as polyalkyleneradicals or poly-C₂₋₆- or poly-C₂₋₄-alkylene radicals. Suitablelong-chain hydrocarbyl radicals and the preparation thereof are alsodescribed, for example, in WO 2006/135881 and the literature citedtherein.

Examples of particularly useful polyalkylene radicals are polyisobutenylradicals derived from “high-reactivity” polyisobutenes which are notablefor a high content of terminal double bonds. Terminal double bonds arealpha-olefinic double bonds of the type

which are also referred to collectively as vinylidene double bonds.Suitable high-reactivity polyisobutenes are, for example, polyisobuteneswhich have a proportion of vinylidene double bonds of greater than 70mol %, especially greater than 80 mol % or greater than 85 mol %.Preference is given especially to polyisobutenes which have homogeneouspolymer structures. Homogeneous polymer structures are possessedespecially by those polyisobutenes formed from isobutene units to anextent of at least 85% by weight, preferably to an extent of at least90% by weight and more preferably to an extent of at least 95% byweight. Such high-reactivity polyisobutenes preferably have anumber-average molecular weight within the abovementioned range. Inaddition, the high-reactivity polyisobutenes may have a polydispersityin the range from 1.05 to 7, especially of about 1.1 to 2.5, for exampleof less than 1.9 or less than 1.5. Polydispersity is understood to meanthe quotient of weight-average molecular weight Mw divided by thenumber-average molecular weight Mn.

Particularly suitable high-reactivity polyisobutenes are, for example,the Glissopal brands from BASF SE, especially Glissopal 1000 (Mn=1000),Glissopal V 33 (Mn=550) and Glissopal 2300 (Mn=2300), and mixturesthereof. Other number-average molecular weights can be established in amanner known in principle by mixing polyisobutenes of differentnumber-average molecular weights or by extractive enrichment ofpolyisobutenes of particular molecular weight ranges.

“Short-chain hydrocarbyl” or “low molecular weight hydrocarbyl” isespecially straight-chain or branched alkyl or alkenyl, optionallyinterrupted by one or more, for example 2, 3 or 4, heteroatom groupssuch as —O— or —NH—, or optionally mono- or polysubstituted, for exampledi-, tri- or tetrasubstituted.

“Short-chain hydrocarbyloxy” or “low molecular weight hydrocarbyloxy” isespecially straight-chain or branched alkyloxy or alkenyloxy, optionallyinterrupted by one or more, for example 2, 3 or 4, heteroatom groupssuch as —O— or —NH—, or optionally mono- or polysubstituted, for exampledi-, tri- or tetrasubstituted.

“Hydroxyl-substituted hydrocarbyl” or “hydroxyhydrocarbyl” representsespecially the hydroxyl-substituted analogs of the alkyl or alkenylradicals defined herein.

“Alkyl” or “lower alkyl” represents especially saturated, straight-chainor branched hydrocarbon radicals having 1 to 4, 1 to 6, 1 to 8, or 1 to10 or 1 to 20, carbon atoms, for example methyl, ethyl, n-propyl,1-methylethyl, n-butyl, 1-methylpropyl, 2-methylpropyl,1,1-dimethylethyl, n-pentyl, 1-methylbutyl, 2-methylbutyl,3-methylbutyl, 2,2-dimethylpropyl, 1-ethylpropyl, n-hexyl,1,1-dimethylpropyl, 1,2-dimethylpropyl, 1-methylpentyl, 2-methyl pentyl,3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl,1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl,3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1,1,2-trimethylpropyl,1,2,2-trimethylpropyl, 1-ethyl-1-methylpropyl and1-ethyl-2-methylpropyl; and also n-heptyl, n-octyl, n-nonyl and n-decyl,and the singly or multiply branched analogs thereof.

“Hydroxyalkyl” represents especially the mono- or polyhydroxylated,especially monohydroxylated, analogs of the above alkyl radicals, forexample the monohydroxylated analogs of the above straight-chain orbranched alkyl radicals, for example the linear hydroxyalkyl groups witha primary hydroxyl group, such as hydroxymethyl, 2-hydroxyethyl,3-hydroxypropyl, 4-hydroxybutyl.

“Alkenyl” represents mono- or polyunsaturated, especiallymonounsaturated, straight-chain or branched hydrocarbon radicals having2 to 4, 2 to 6, 2 to 8, 2 to 10 or 2 to 20 carbon atoms and a doublebond in any position, for example C₂-C₆-alkenyl such as ethenyl,1-propenyl, 2-propenyl, 1-methylethenyl, 1-butenyl, 2-butenyl,3-butenyl, 1-methyl-1-propenyl, 2-methyl-1-propenyl,1-methyl-2-propenyl, 2-methyl-2-propenyl, 1-pentenyl, 2-pentenyl,3-pentenyl, 4-pentenyl, 1-methyl-1-butenyl, 2-methyl-1-butenyl,3-methyl-1-butenyl, 1-methyl-2-butenyl, 2-methyl-2-butenyl,3-methyl-2-butenyl, 1-methyl-3-butenyl, 2-methyl-3-butenyl,3-methyl-3-butenyl, 1,1-dimethyl-2-propenyl, 1,2-dimethyl-1-propenyl,1,2-dimethyl-2-propenyl, 1-ethyl-1-propenyl, 1-ethyl-2-propenyl,1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, 5-hexenyl,1-methyl-1-pentenyl, 2-methyl-1-pentenyl, 3-methyl-1-pentenyl,4-methyl-1-pentenyl, 1-methyl-2-pentenyl, 2-methyl-2-pentenyl,3-methyl-2-pentenyl, 4-methyl-2-pentenyl, 1-methyl-3-pentenyl,2-methyl-3-pentenyl, 3-methyl-3-pentenyl, 4-methyl-3-pentenyl,1-methyl-4-pentenyl, 2-methyl-4-pentenyl, 3-methyl-4-pentenyl,4-methyl-4-pentenyl, 1,1-dimethyl-2-butenyl, 1,1-dimethyl-3-butenyl,1,2-dimethyl-1-butenyl, 1,2-dimethyl-2-butenyl, 1,2-dimethyl-3-butenyl,1,3-dimethyl-1-butenyl, 1,3-dimethyl-2-butenyl, 1,3-dimethyl-3-butenyl,2,2-dimethyl-3-butenyl, 2,3-dimethyl-1-butenyl, 2,3-dimethyl-2-butenyl,2,3-dimethyl-3-butenyl, 3,3-dimethyl-1-butenyl, 3,3-dimethyl-2-butenyl,1-ethyl-1-butenyl, 1-ethyl-2-butenyl, 1-ethyl-3-butenyl,2-ethyl-1-butenyl, 2-ethyl-2-butenyl, 2-ethyl-3-butenyl,1,1,2-trimethyl-2-propenyl, 1-ethyl-1-methyl-2-propenyl,1-ethyl-2-methyl-1-propenyl and 1-ethyl-2-methyl-2-propenyl.

“Hydroxyalkenyl” represents especially the mono- or polyhydroxylated,especially monohydroxylated, analogs of the above alkenyl radicals.

“Alkyloxy” and “alkenyloxy” represent especially the oxygen-bondedanalogs of the above “alkyl” and “alkenyl” radicals.

“Alkylene” represents straight-chain or mono- or polybranchedhydrocarbon bridge groups having 1 to 10 carbon atoms, for exampleC₁-C₇-alkylene groups selected from —CH₂—, —(CH₂)₂—, —(CH₂)₃—, —(CH₂)₄—,—(CH₂)₂—CH(CH₃)—, —CH₂—CH(CH₃)—CH₂—, (CH₂)₄—, —(CH₂)₅—, —(CH₂)₆,—(CH₂)₇—, —CH(CH₃)—CH₂—CH₂—CH(CH₃)— or —CH(CH₃)—CH₂—CH₂—CH₂—CH(CH₃)— orC₁-C₄-alkylene groups selected from —CH₂—, —(CH₂)₂—, —(CH₂)₃—, —(CH₂)₄—,—(CH₂)₂—CH(CH₃)—, —CH₂—CH(CH₃)—CH₂; or C₂-C₆-alkylene groups, as forexample —CH₂—CH(CH₃)—, —CH(CH₃)—CH₂—, —CH(CH₃)—CH(CH₃)—, —C(CH₃)₂—CH₂—,—CH₂—C(CH₃)₂—, —C(CH₃)₂—CH(CH₃)—, —CH(CH₃)—C(CH₃)₂—, —CH₂—CH(CH₂CH₃)—,—CH(CH₂CH₃)—CH₂—, —CH(CH₂CH₃)—CH(CH₂CH₃)—, —C(CH₂CH₃)₂—CH₂—,—CH₂—C(CH₂CH₃)₂—, —CH₂—CH(n-propyl), —CH(n-propyl)-CH₂—,—CH(n-propyl)-CH(CH₃)—, —CH₂—CH(n-butyl), —CH(n-butyl)-CH₂—,—CH(CH₃)—CH(CH₂CH₃)—, —CH(CH₃)—CH(n-propyl)-, —CH(CH₂CH₃)—CH(CH₃)—,—CH(CH₃)—CH(CH₂CH₃)—, or C₂-C₄-alkylene groups, as for example —(CH₂)₂—,—CH₂—CH(CH₃)—, —CH(CH₃)—CH₂—, —CH(CH₃)—CH(CH₃)—, —C(CH₃)₂—CH₂—,—CH₂—C(CH₃)₂—, —CH₂—CH(CH₂CH₃)—, —CH(CH₂CH₃)—CH₂—.

“Alkenylene” represents the mono- or polyunsaturated, especiallymonounsaturated, analogs of the above alkylene groups having 2 to 10carbon atoms, especially C₂-C₇-alkenylenes or C₂-C₄-alkenylenes, such as—CH═CH—, —CH═CH—CH₂—, —CH₂—CH═CH—, —CH═CH—CH₂—CH₂—, —CH₂—CH═CH—CH₂—,—CH₂—CH₂—CH═CH—, —CH(CH₃)—CH═CH—, —CH₂—C(CH₃)═CH—.

“Acyl” represents radicals derived from straight-chain or branched,optionally mono- or polyunsaturated, optionally substituted C₁-C₂₄,especially C₁-C₁₂ or C₁-C₈, monocarboxylic acids. For example, usefulacyl radicals are derived from the following carboxylic acids: saturatedacids such as formic acid, acetic acid, propionic acid and n- andi-butyric acid, n- and i-valeric acid, caproic acid, enanthic acid,caprylic acid, pelargonic acid, capric acid, undecanoic acid, lauricacid, tridecanoic acid, myristic acid, pentadecanoic acid, palmiticacid, margaric acid, stearic acid, nonadecanoic acid, arachic acid,behenic acid, lignoceric acid, cerotic acid and melissic acid;monounsaturated acids such as acrylic acid, crotonic acid, palmitoleicacid, oleic acid and erucic acid; and diunsaturated acids such as sorbicacid and linoleic acid. When double bonds are present in the fattyacids, they may either be in cis form or in trans form.

“Cyclic hydrocarbyl radicals” comprise especially:

-   -   cycloalkyl: carbocyclic radicals having 3 to 20 carbon atoms,        for example C₃-C₁₂-cycloalkyl such as cyclopropyl, cyclobutyl,        cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl,        cyclodecyl, cycloundecyl and cyclododecyl; preference is given        to cyclopentyl, cyclohexyl, cycloheptyl, and also to        cyclopropylmethyl, cyclopropylethyl, cyclobutylmethyl,        cyclobutylethyl, cyclopentylmethyl, cyclopentylethyl,        cyclohexylmethyl, or C₃-C₇-cycloalkyl such as cyclopropyl,        cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl,        cyclopropylmethyl, cyclopropylethyl, cyclobutylmethyl,        cyclopentylethyl, cyclohexylmethyl, where the bond to the rest        of the molecule may be via any suitable carbon atom.    -   cycloalkenyl: monocyclic, monounsaturated hydrocarbon groups        having 5 to 8, preferably up to 6, carbon ring members, such as        cyclopenten-1-yl, cyclopenten-3-yl, cyclohexen-1-yl,        cyclohexen-3-yl and cyclohexen-4-yl;    -   aryl: mono- or polycyclic, preferably mono- or bicyclic,        optionally substituted aromatic radicals having 6 to 20, for        example 6 to 10, ring carbon atoms, for example phenyl,        biphenyl, naphthyl such as 1- or 2-naphthyl, tetrahydronaphthyl,        fluorenyl, indenyl and phenanthrenyl. These aryl radicals may        optionally bear 1, 2, 3, 4, 5 or 6 identical or different        substituents.    -   arylalkyl: the aryl-substituted analogs of the above alkyl        radicals, where aryl is likewise as defined above, for example        phenyl-C₁-C₄-alkyl radicals selected from phenylmethyl and        phenylethyl.    -   heterocyclyl: five- to seven-membered saturated, partially        unsaturated or aromatic (=heteroaryl or hetaryl) heterocycles or        heterocyclyl radicals comprising one, two, three or four        heteroatoms from the group of O, N and S. For example, the        following subgroups may be mentioned:        -   5- or 6-membered saturated or monounsaturated heterocyclyl            comprising one or two nitrogen atoms and/or one oxygen or            sulfur atom or one or two oxygen and/or sulfur atoms as ring            members, for example 2-tetrahydrofuranyl,            3-tetrahydrofuranyl, 2-tetrahydrothienyl,            3-tetrahydrothienyl, 1-pyrrolidinyl, 2-pyrrolidinyl,            3-pyrrolidinyl, 3-isoxazolidinyl, 4-isoxazolidinyl,            5-isoxazolidinyl, 3-isothiazolidinyl, 4-isothiazolidinyl,            5-isothiazolidinyl, 3-pyrazolidinyl, 4-pyrazolidinyl,            5-pyrazolidinyl, 2-oxazolidinyl, 4-oxazolidinyl,            5-oxazolidinyl, 2-thiazolidinyl, 4-thiazolidinyl,            5-thiazolidinyl, 2-imidazolidinyl, 4-imidazolidinyl,            2-pyrrolin-2-yl, 2-pyrrolin-3-yl, 3-pyrrolin-2-yl,            3-pyrrolin-3-yl, 1-piperidinyl, 2-piperidinyl,            3-piperidinyl, 4-piperidinyl, 1,3-dioxan-5-yl,            2-tetrahydropyranyl, 4-tetrahydropyranyl,            2-tetrahydrothienyl, 3-hexahydropyridazinyl,            4-hexahydropyridazinyl, 2-hexahydropyrimidinyl,            4-hexahydropyrimidinyl, 5-hexahydropyrimidinyl and            2-piperazinyl;        -   5-membered aromatic heterocyclyl comprising, as well as            carbon atoms, one, two or three nitrogen atoms or one or two            nitrogen atoms and one sulfur or oxygen atom as ring            members, for example 2-furyl, 3-furyl, 2-thienyl, 3-thienyl,            2-pyrrolyl, 3-pyrrolyl, 3-pyrazolyl, 4-pyrazolyl,            5-pyrazolyl, 2-oxazolyl, 4-oxazolyl, 5-oxazolyl,            2-thiazolyl, 4-thiazolyl, 5-thiazolyl, 2-imidazolyl,            4-imidazolyl, and 1,3,4-triazol-2-yl;        -   5-membered aromatic heterocyclyl which has 1, 2, 3 or 4            nitrogen atoms as ring members, such as 1-, 2- or            3-pyrrolyl, 1-, 3- or 4-pyrazolyl, 1-, 2- or 4-imidazolyl,            1,2,3-[1H]-triazol-1-yl, 1,2,3-[2H]-triazol-2-yl,            1,2,3-[1H]-triazol-4-yl, 1,2,3-[1H]-triazol-5-yl,            1,2,3-[2H]-triazol-4-yl, 1,2,4-[1H]-triazol-1-yl,            1,2,4-[1H]-triazol-3-yl, 1,2,4-[1H]-triazol-5-yl,            1,2,4-[4H]-triazol-4-yl, 1,2,4-[4H]-triazol-3-yl,            [1H]-tetrazol-1-yl, [1H]-tetrazol-5-yl, [2H]-tetrazol-2-yl            and [2H]-tetrazol-5-yl;        -   5-membered aromatic heterocyclyl which has 1 heteroatom            selected from oxygen and sulfur and optionally 1, 2 or 3            nitrogen atoms as ring members, for example 2-furyl,            3-furyl, 2-thienyl, 3-thienyl, 3- or 4-isoxazolyl, 3- or            4-isothiazolyl, 2-, 4- or 5-oxazolyl, 2-, 4- or 5-thiazolyl,            1,2,4-thiadiazol-3-yl, 1,2,4-thiadiazol-5-yl,            1,3,4-thiadiazol-2-yl, 1,2,4-oxadiazol-3-yl,            1,2,4-oxadiazol-5-yl and 1,3,4-oxadiazol-2-yl;        -   6-membered heterocyclyl comprising, as well as carbon atoms,            one or two, or one, two or three, nitrogen atoms as ring            members, for example 2-pyridinyl, 3-pyridinyl, 4-pyridinyl,            3-pyridazinyl, 4-pyridazinyl, 2-pyrimidinyl, 4-pyrimidinyl,            5-pyrimidinyl, 2-pyrazinyl, 1,2,4-triazin-3-yl;            1,2,4-triazin-5-yl, 1,2,4-triazin-6-yl and            1,3,5-triazin-2-yl.

“Substituents” for radicals specified herein are especially selectedfrom keto groups, —COOH, —COO-alkyl, —OH, —SH, —CN, amino, —NO₂, alkyl,or alkenyl groups.

A3) Polycarboxylic Anhydride Compounds, Such as EspeciallyPolycarboxylic Anhydrides and Hydrocarbyl-Substituted PolycarboxylicAnhydrides

The anhydride used is derived from any aliphatic di- or polybasiccarboxylic acids (for example tri- or tetrabasic), especially from di-,tri- or tetracarboxylic acids, and is optionally substituted by one ormore (for example 2 or 3), especially a long-chain alkyl radical and/ora high molecular weight hydrocarbyl radical, especially a polyalkyleneradical. Examples are anhydrides of C₃-C₁₀ polycarboxylic acids, such asthe dicarboxylic acids malonic acid, succinic acid, glutaric acid,adipic acid, pimelic acid, suberic acid, azelaic acid and sebacic acid,and the branched analogs thereof; and the tricarboxylic acid citricacid. The anhydrides can also be obtained from the correspondingmonounsaturated acids and addition of at least one long-chain alkylradical and/or high molecular weight hydrocarbyl radical. Examples ofsuitable monounsaturated acids are fumaric acid, maleic acid, itaconicacid.

The hydrophobic “long-chain” or “high molecular weight” hydrocarbylradical which ensures sufficient solubility of the quaternized productin the fuel has a number-average molecular weight (M_(n)) of 85 to 20000, for example 113 to 10 000, or 200 to 10 000 or 350 to 5000, forexample 350 to 3000, 500 to 2500, 700 to 2500, or 800 to 1500. Typicalhydrophobic hydrocarbyl radicals include polypropenyl, polybutenyl andpolyisobutenyl radicals, for example with a number-average molecularweight M_(n) of 3500 to 5000, 350 to 3000, 500 to 2500, 700 to 2500 and800 to 1500.

Suitable hydrocarbyl-substituted anhydrides are described, for example,in DE 43 19 672 and WO 2008/138836.

Suitable hydrocarbyl-substituted polycarboxylic anhydrides also comprisepolymeric, especially dimeric, forms of such hydrocarbyl-substitutedpolycarboxylic anhydrides.

Dimeric forms comprise especially two acid anhydride groups which can bereacted independently with the quaternizable nitrogen compound in thepreparation process according to the invention.

A4) Quaternizing Agents

Useful quaternizing agents are in principle all compounds suitable assuch. In a particular embodiment, however, the at least onequaternizable tertiary nitrogen atom is quaternized with at least onequaternizing agent selected from epoxides, especially hydrocarbylepoxides:

in which the R^(a) radicals present therein are the same or differentand are each H or a hydrocarbyl radical, where the hydrocarbyl radicalhas at least 1 to 10 carbon atoms. In particular, these are aliphatic oraromatic radicals, for example linear or branched C₁₋₁₀-alkyl radicals,or aromatic radicals, such as phenyl or C₁₋₄-alkylphenyl.

Suitable hydrocarbyl epoxides are, for example, aliphatic and aromaticalkylene oxides, such as especially C₂₋₁₂-alkylene oxides, such asethylene oxide, propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide,2-methyl-1,2-propene oxide (isobutene oxide), 1,2-pentene oxide,2,3-pentene oxide, 2-methyl-1,2-butene oxide, 3-methyl-1,2-butene oxide,1,2-hexene oxide, 2,3-hexene oxide, 3,4-hexene oxide,2-methyl-1,2-pentene oxide, 2-ethyl-1,2-butene oxide,3-methyl-1,2-pentene oxide, 1,2-decene oxide, 1,2-dodecene oxide or4-methyl-1,2-pentene oxide; and also aromatic-substituted ethyleneoxides, such as optionally substituted styrene oxide, especially styreneoxide or 4-methylstyrene oxide.

In the case of use of epoxides as quaternizing agents, they are usedespecially in the absence of free acids, especially in the absence offree protic acids, such as in particular C₁₋₁₂-monocarboxylic acids suchas formic acid, acetic acid or propionic acid, or C₂₋₁₂-dicarboxylicacids such as oxalic acid or adipic acid; or else in the absence ofsulfonic acids such as benzenesulfonic acid or toluenesulfonic acid, oraqueous mineral acids such as sulfuric acid or hydrochloric acid. Thequaternization product thus prepared is thus “acid-free” in the contextof the present invention.

A5) Quaternized or Quaternizable Nitrogen Compounds

The quaternizable nitrogen compound reactive with the anhydride isselected from

-   a. hydroxyalkyl-substituted mono- or polyamines having at least one    quaternized (e.g. choline) or quaternizable primary, secondary or    tertiary amino group;-   b. straight-chain or branched, cyclic, heterocyclic, aromatic or    nonaromatic polyamines having at least one primary or secondary    (anhydride-reactive) amino group and having at least one quaternized    or quaternizable primary, secondary or tertiary amino group;-   c. piperazines.

The quaternizable nitrogen compound is especially selected from

-   a. hydroxyalkyl-substituted primary, secondary, tertiary or    quaternary monoamines and hydroxyalkyl-substituted primary,    secondary, tertiary or quaternary diamines;-   b. straight-chain or branched aliphatic diamines having two primary    amino groups; di- or polyamines having at least one primary and at    least one secondary amino group; di- or polyamines having at least    one primary and at least one tertiary amino group; di- or polyamines    having at least one primary and at least one quaternary amino group;    aromatic carbocyclic diamines having two primary amino groups;    aromatic heterocyclic polyamines having two primary amino groups;    aromatic or nonaromatic heterocycles having one primary and one    tertiary amino group.

Examples of suitable “hydroxyalkyl-substituted mono- or polyamines” arethose provided with at least one hydroxyalkyl substituents, for example1, 2, 3, 4, 5 or 6 hydroxyalkyl substituted.

Examples of “hydroxyalkyl-substituted monoamines” include:N-hydroxyalkyl monoamines, N,N-dihydroxyalkyl monoamines andN,N,N-trihydroxyalkyl monoamines, where the hydroxyalkyl groups are thesame or different and are also as defined above. Hydroxyalkyl isespecially 2-hydroxyethyl, 3-hydroxypropyl or 4-hydroxybutyl.

For example, the following “hydroxyalkyl-substituted polyamines” andespecially “hydroxyalkyl-substituted diamines” may be mentioned:(N-hydroxyalkyl)alkylenediamines, N,N-dihydroxyalkylalkylenediamines,where the hydroxyalkyl groups are the same or different and are also asdefined above. Hydroxyalkyl is especially 2-hydroxyethyl,3-hydroxypropyl or 4-hydroxybutyl; alkylene is especially ethylene,propylene or butylene.

Suitable “diamines” are alkylenediamines, and the N-alkyl-substitutedanalogs thereof, such as N-monoalkylated alkylenediamines and the N,N-or N,N′-dialkylated alkylenediamines. Alkylene is especiallystraight-chain or branched C₁₋₇- or C₁₋₄-alkylene as defined above.Alkyl is especially C₁₋₄-alkyl as defined above. Examples are inparticular ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine,1,4-butylenediamine and isomers thereof, pentanediamine and isomersthereof, hexanediamine and isomers thereof, heptanediamine and isomersthereof, as well as singly or multiply, like one- or two-foldC₁-C₄-alkylated, as for example methylated, derivates of said diaminecompounds, as for example 3-dimethylamino-1-propylamine (DMAPA),N,N-diethylaminopropylamine, and N,N-dimethylaminoethylamine.

Suitable straight-chain “polyamines” are, for example,dialkylenetriamine, trialkylenetetramine, tetraalkylenepentamine,pentaalkylenehexamine, and the N-alkyl-substituted analogs thereof, suchas N-monoalkylated and the N,N- or N,N′-dialkylated alkylenepolyamines.Alkylene is especially straight-chain or branched C₁₋₇- or C₁₋₄-alkyleneas defined above. Alkyl is especially C₁₋₄-alkyl as defined above.

Examples are especially diethylenetriamine, triethylenetetramine,tetraethylenepentamine, pentaethylenehexamine, dipropylenetriamine,tripropylenetetramine, tetrapropylenepentamine, pentapropylenehexamine,dibutylenetriamine, tributylenetetramine, tetrabutylenepentamine,pentabutylenehexamine; and the N,N-dialkyl derivatives thereof,especially the N,N-di-C₁₋₄-alkyl derivatives thereof. Examples include:N,N-dimethyldimethylenetriamine, N,N-diethyldimethylenetriamine,N,N-dipropyldimethylenetriamine, N,N-dimethyldiethylene-1,2-triamine,N,N-diethyldiethylene-1,2-triamine, N,N-dipropyldiethylene-1,2-triamine,N,N-dimethyldipropylene-1,3-triamine (i.e. DMAPAPA),N,N-diethyldipropylene-1,3-triamine,N,N-dipropyldipropylene-1,3-triamine,N,N-dimethyldibutylene-1,4-triamine, N,N-diethyldibutylene-1,4-triamine,N,N-dipropyldibutylene-1,4-triamine,N,N-dimethyldipentylene-1,5-triamine,N,N-diethyldipentylene-1,5-triamine,N,N-dipropyldipentylene-1,5-triamine,N,N-dimethyldihexylene-1,6-triamine, N,N-diethyldihexylene-1,6-triamineand N,N-dipropyldihexylene-1,6-triamine.

“Aromatic carbocyclic diamines” having two primary amino groups are thediamino-substituted derivatives of benzene, biphenyl, naphthalene,tetrahydronaphthalene, fluorene, indene and phenanthrene.

“Aromatic or nonaromatic heterocyclic polyamines” having two primaryamino groups are the derivatives, substituted by two amino groups, ofthe following heterocycles:

-   -   5- or 6-membered, saturated or monounsaturated heterocycles        comprising one to two nitrogen atoms and/or one oxygen or sulfur        atom or one or two oxygen and/or sulfur atoms as ring members,        for example tetrahydrofuran, pyrrolidine, isoxazolidine,        isothiazolidine, pyrazolidine, oxazolidine, thiazolidine,        imidazolidine, pyrroline, piperidine, piperidinyl, 1,3-dioxane,        tetrahydropyran, hexahydropyridazine, hexahydropyrimidine,        piperazine;    -   5-membered aromatic heterocycles comprising, in addition to        carbon atoms, two or three nitrogen atoms or one or two nitrogen        atoms and one sulfur or oxygen atom as ring members, for example        furan, thiane, pyrrole, pyrazole, oxazole, thiazole, imidazole        and 1,3,4-triazole; isoxazole, isothiazole, thiadiazole,        oxadiazole;    -   6-membered heterocycles comprising, in addition to carbon atoms,        one or two, or one, two or three, nitrogen atoms as ring        members, for example pyridinyl, pyridazine, pyrimidine,        pyrazinyl, 1,2,4-triazine, 1,3,5-triazin-2-yl.

“Aromatic or nonaromatic heterocycles having one primary and onetertiary amino group” are, for example, the abovementionedN-heterocycles which are aminoalkylated on at least one ring nitrogenatom, and especially bear an amino-C₁₋₄-alkyl group.

“Aromatic or nonaromatic heterocycles having a tertiary amino group anda hydroxyalkyl group” are, for example, the abovementionedN-heterocycles which are hydroxyalkylated on at least one ring nitrogenatom, and especially bear a hydroxy-C₁₋₄-alkyl group.

Mention should be made especially of the following groups of individualclasses of quaternizable nitrogen compounds:

Group 1:

NAME FORMULA Diamines with primary second nitrogen atom Ethylenediamine

1,2-Propylenediamine

1,3-Propylenediamine

Isomeric butylenediamines, for example

1,5-Pentylenediamine

Isomeric pentanediamines, for example

Isomeric hexanediamines, for example

Isomeric heptanediamines, for example

Di- and polyamines with a secondary second nitrogen atomDiethylenetriamine (DETA)

Dipropylenetriamine (DPTA), 3,3′- iminobis(N,N-dimethylpropylamine)

Triethylenetetramine (TETA)

Tetraethylenepentamine (TEPA)

Pentaethylenehexamine

N-Methyl-3-amino-1-propylamine

Bishexamethylenetriamine

Aromatics Diaminobenzenes, for example

Diaminopyridines, for example

Group 2:

NAME FORMULA Heterocycles 1-(3-Aminopropyl)imidazole

4-(3-Aminopropyl)morpholine

1-(2-Aminoethylpiperidine)

2-(1-Piperazinyl)ethylamine (AEP)

N-Methylpiperazine

Amines with a tertiary second nitrogen atom3,3-Diamino-N-methyldipropylamine

3-Dimethylamino-1-propylamine (DMAPA)

N,N-Diethylaminopropylamine

N,N-Dimethylaminoethylamine

Group 3:

NAME FORMULA Alcohols with a primary and secondary amine Ethanolamine

3-Hydroxy-1-propylamine

Diethanolamine

Diisopropanolamine

N-(2-Hydroxyethyl)ethylenediamine

Alcohols with a tertiary amine Triethanolamine,(2,2^(|),2^(||)-Nitrilotriethanol)

1-(3-Hydroxypropyl)imidazole

Tris(hydroxymethyl)amine

3-Dimethylamino-1-propanol

3-Diethylamino-1-propanol

2-Dimethylamino-1-ethanol

4-Diethylamino-1-butanol

A6) Preparation of Inventive Additivesa) Amine Addition and Alcohol Addition

The hydrocarbyl-substituted polycarboxylic anhydride compound is reactedwith the quaternizable nitrogen compound under thermally controlledconditions, such that there is essentially no condensation reaction.More particularly, in accordance with the invention, no formation ofwater of reaction is observed. More particularly, the reaction iseffected at a temperature in the range from 10 to 80° C., especially 20to 60° C. or 30 to 50° C. The reaction time may be in the range from afew minutes or a few hours, for example about 1 minute up to about 10hours. The reaction can be effected at a pressure of about 0.1 to 2 atm,but especially at approximately standard pressure. In particular, aninert gas atmosphere, for example nitrogen, is appropriate.

The reactants are initially charged especially in about equimolaramounts; optionally, a small molar excess of the anhydride, for examplea 0.05- to 0.5-fold, for example a 0.1- to 0.3-fold, excess, isdesirable. If required, the reactants can be initially charged in asuitable inert organic aliphatic or aromatic solvent or a mixturethereof. Typical examples are, for example, solvents of the Solvessoseries, toluene or xylene. However, in another particular embodiment,the reaction is effected in the absence of organic solvents, especiallyprotic solvents.

In the case of inventive performance of the reaction, the anhydride ringis opened with addition of the quaternizable nitrogen compound via thereactive oxygen or nitrogen group thereof (for example hydroxyl group orprimary or secondary amine group), and without the elimination of waterof condensation. The reaction product obtained comprises apolycarboxylic intermediate with at least one newly formed acid amidegroup or ester group and at least one intramolecular, bound, newlyformed carboxylic acid or carboxylate group, in a stoichiometricproportion relative to the quaternizable amino group boundintramolecularly by the addition reaction.

The reaction product thus formed can theoretically be purified further,or the solvent can be removed. Usually, however, this is not absolutelynecessary, such that the reaction step can be transferred withoutfurther purification into the next synthesis step, the quaternization.

b) Quaternization

The epoxide-based quaternization in reaction step (b) is then carriedout without addition of acid, in a complete renunciation of prior artmethods described to date. The carboxyl radical formed by amine additionpromotes the epoxide ring opening and hence the quaternization of theamino group. The reaction product obtained therefore does not have afree acid anion. Nevertheless, the product is uncharged owing to itsbetaine structure.

To perform the quaternization, the reaction product or reaction mixturefrom stage a) is admixed with at least one epoxide compound of the aboveformula (II), especially in the stoichiometric amounts required toachieve the desired quaternization. It is possible to use, for example,0.1 to 1.5 equivalents, or 0.5 to 1.25 equivalents, of quaternizingagent per equivalent of quaternizable tertiary nitrogen atom. Moreparticularly, however, approximately equimolar proportions of theepoxide are used to quaternize a tertiary amine group. Correspondinglyhigher use amounts are required to quaternize a secondary or primaryamine group.

Typical working temperatures here are in the range from 15 to 90° C.,especially from 20 to 80° C. or 30 to 70° C. The reaction time may be inthe range of a few minutes or a few hours, for example about 10 minutesup to about 24 hours. The reaction can be effected at a pressure ofabout 0.1 to 20 bar, for example 1 to 10 or 1.5 to 3 bar, but especiallyat about standard pressure. More particularly, an inert gas atmosphere,for example nitrogen, is appropriate.

If required, the reactants can be initially charged for the epoxidationin a suitable inert organic aliphatic or aromatic solvent or a mixturethereof, or a sufficient proportion of solvent from reaction step a) isstill present. Typical examples are, for example, solvents of theSolvesso series, toluene or xylene. In a further particular embodiment,the reaction, however, is performed in the absence of organic solvents,especially protic (organic) solvents.

“Protic solvents”, which are especially not used in accordance with theinvention, are especially those with a dielectric constant of greaterthan 9. Such protic solvents usually comprise at least one HO group andmay additionally contain water. Typical examples are, for example,glycols and glycol ethers, and alcohols such as aliphatic,cyclic-aliphatic, aromatic or heterocyclic alcohols.

c) Workup of the Reaction Mixture

The reaction end product thus formed can theoretically be purifiedfurther, or the solvent can be removed. Usually, however, this is notabsolutely necessary, and so the reaction product is usable withoutfurther purification as an additive, optionally after blending withfurther additive components (see below), especially since there are ofcourse also no corrosive free protic acids present in the reactionproduct.

d) General Example

As a nonlimiting example of the reaction of a polyalkylene-substituteddicarboxylic anhydride compound by amine addition or alcohol additionand subsequent quaternization, reference is made to the followingillustrative reaction schemes in which R₁ to R₇, L₁ and L₂ are each asdefined above:

Stage 1: Preparation of the Substituted Dicarboxylic Anhydride

Stage 2a: Amination and Quaternization

Stage 2b: Ester Formation and Quaternization

B) Further Additive Components

The fuel additized with the inventive quaternized additive is a gasolinefuel or especially a middle distillate fuel, in particular a dieselfuel.

The fuel may comprise further customary additives to improve efficacyand/or suppress wear.

In the case of diesel fuels, these are primarily customary detergentadditives, carrier oils, cold flow improvers, lubricity improvers,corrosion inhibitors, demulsifiers, dehazers, antifoams, cetane numberimprovers, combustion improvers, antioxidants or stabilizers, antistats,metallocenes, metal deactivators, dyes and/or solvents.

In the case of gasoline fuels, these are in particular lubricityimprovers (friction modifiers), corrosion inhibitors, demulsifiers,dehazers, antifoams, combustion improvers, antioxidants or stabilizers,antistats, metallocenes, metal deactivators, dyes and/or solvents.

Typical examples of suitable coadditives are listed in the followingsection:

B1) Detergent Additives

The customary detergent additives are preferably amphiphilic substanceswhich possess at least one hydrophobic hydrocarbon radical with anumber-average molecular weight (M_(n)) of 85 to 20 000 and at least onepolar moiety selected from:

-   (Da) mono- or polyamino groups having up to 6 nitrogen atoms, at    least one nitrogen atom having basic properties;-   (Db) nitro groups, optionally in combination with hydroxyl groups;-   (Dc) hydroxyl groups in combination with mono- or polyamino groups,    at least one nitrogen atom having basic properties;-   (Dd) carboxyl groups or their alkali metal or alkaline earth metal    salts;-   (De) sulfonic acid groups or their alkali metal or alkaline earth    metal salts;-   (Df) polyoxy-C₂- to C₄-alkylene moieties terminated by hydroxyl    groups, mono- or polyamino groups, at least one nitrogen atom having    basic properties, or by carbamate groups;-   (Dg) carboxylic ester groups;-   (Dh) moieties derived from succinic anhydride and having hydroxyl    and/or amino and/or amido and/or imido groups; and/or-   (Di) moieties obtained by Mannich reaction of substituted phenols    with aldehydes and mono- or polyamines.

The hydrophobic hydrocarbon radical in the above detergent additives,which ensures the adequate solubility in the fuel, has a number-averagemolecular weight (M_(n)) of 85 to 20 000, preferably of 113 to 10 000,more preferably of 300 to 5000, even more preferably of 300 to 3000,even more especially preferably of 500 to 2500 and especially of 700 to2500, in particular of 800 to 1500. As typical hydrophobic hydrocarbonradicals, especially in conjunction with the polar groups especiallypolypropenyl, polybutenyl and polyisobutenyl radicals with anumber-average molecular weight M_(n) of preferably in each case 300 to5000, more preferably 300 to 3000, even more preferably 500 to 2500,even more especially preferably 700 to 2500 and especially 800 to 1500are taken into consideration.

Examples of the above groups of detergent additives include thefollowing:

Additives comprising mono- or polyamino groups (Da) are preferablypolyalkenemono- or polyalkenepolyamines based on polypropene or onhigh-reactivity (i.e. having predominantly terminal double bonds) orconventional (i.e. having predominantly internal double bonds)polybutene or polyisobutene having M_(n)=300 to 5000, more preferably500 to 2500 and especially 700 to 2500. Such additives based onhigh-reactivity polyisobutene, which can be prepared from thepolyisobutene which may comprise up to 20% by weight of n-butene unitsby hydroformylation and reductive amination with ammonia, monoamines orpolyamines such as dimethylaminopropylamine, ethylenediamine,diethylenetriamine, triethylenetetramine or tetraethylenepentamine, areknown especially from EP-A 244 616. When polybutene or polyisobutenehaving predominantly internal double bonds (usually in the β and γpositions) are used as starting materials in the preparation of theadditives, a possible preparative route is by chlorination andsubsequent amination or by oxidation of the double bond with air orozone to give the carbonyl or carboxyl compound and subsequent aminationunder reductive (hydrogenating) conditions. The amines used here for theamination may be, for example, ammonia, monoamines or the abovementionedpolyamines. Corresponding additives based on polypropene are describedin particular in WO-A 94/24231.

Further particular additives comprising monoamino groups (Da) are thehydrogenation products of the reaction products of polyisobutenes havingan average degree of polymerization P=5 to 100 with nitrogen oxides ormixtures of nitrogen oxides and oxygen, as described in particular inWO-A 97/03946.

Further particular additives comprising monoamino groups (Da) are thecompounds obtainable from polyisobutene epoxides by reaction with aminesand subsequent dehydration and reduction of the amino alcohols, asdescribed in particular in DE-A 196 20 262.

Additives comprising nitro groups (Db), optionally in combination withhydroxyl groups, are preferably reaction products of polyisobuteneshaving an average degree of polymerization P=5 to 100 or 10 to 100 withnitrogen oxides or mixtures of nitrogen oxides and oxygen, as describedin particular in WO-A 96/03367 and in WO-A 96/03479. These reactionproducts are generally mixtures of pure nitropolyisobutenes (e.g.α,β-dinitropolyisobutene) and mixed hydroxynitropolyisobutenes (e.g.α-nitro-β-hydroxypolyisobutene).

Additives comprising hydroxyl groups in combination with mono- orpolyamino groups (Dc) are in particular reaction products ofpolyisobutene epoxides obtainable from polyisobutene having preferablypredominantly terminal double bonds and M_(n)=300 to 5000, with ammoniaor mono- or polyamines, as described in particular in EP-A 476 485.

Additives comprising carboxyl groups or their alkali metal or alkalineearth metal salts (Dd) are preferably copolymers of C₂- to C₄₀-olefinswith maleic anhydride which have a total molar mass of 500 to 20 000 andsome or all of whose carboxyl groups have been converted to the alkalimetal or alkaline earth metal salts and any remainder of the carboxylgroups has been reacted with alcohols or amines. Such additives aredisclosed in particular by EP-A 307 815. Such additives serve mainly toprevent valve seat wear and can, as described in WO-A 87/01126,advantageously be used in combination with customary fuel detergentssuch as poly(iso)buteneamines or polyetheramines.

Additives comprising sulfonic acid groups or their alkali metal oralkaline earth metal salts (De) are preferably alkali metal or alkalineearth metal salts of an alkyl sulfosuccinate, as described in particularin EP-A 639 632. Such additives serve mainly to prevent valve seat wearand can be used advantageously in combination with customary fueldetergents such as poly(iso)buteneamines or polyetheramines.

Additives comprising polyoxy-C₂-C₄-alkylene moieties (Df) are preferablypolyethers or polyetheramines which are obtainable by reaction of C₂- toC₆₀-alkanols, C₆- to C₃₀-alkanediols, mono- or di-C₂- toC₃₀-alkylamines, C₁- to C₃₀-alkylcyclohexanols or C₁- toC₃₀-alkylphenols with 1 to 30 mol of ethylene oxide and/or propyleneoxide and/or butylene oxide per hydroxyl group or amino group and, inthe case of the polyetheramines, by subsequent reductive amination withammonia, monoamines or polyamines. Such products are described inparticular in EP-A 310 875, EP-A 356 725, EP-A 700 985 and U.S. Pat. No.4,877,416. In the case of polyethers, such products also have carrieroil properties. Typical examples of these are tridecanol butoxylates,isotridecanol butoxylates, isononylphenol butoxylates and polyisobutenolbutoxylates and propoxylates and also the corresponding reactionproducts with ammonia.

Additives comprising carboxylic ester groups (Dg) are preferably estersof mono-, di- or tricarboxylic acids with long-chain alkanols orpolyols, in particular those having a minimum viscosity of 2 mm²/s at100° C., as described in particular in DE-A 38 38 918. The mono-, di- ortricarboxylic acids used may be aliphatic or aromatic acids, andparticularly suitable ester alcohols or ester polyols are long-chainrepresentatives having, for example, 6 to 24 carbon atoms. Typicalrepresentatives of the esters are adipates, phthalates, isophthalates,terephthalates and trimellitates of isooctanol, of isononanol, ofisodecanol and of isotridecanol. Such products also have carrier oilproperties.

Additives comprising moieties derived from succinic anhydride and havinghydroxyl and/or amino and/or amido and/or especially imido groups (Dh)are preferably corresponding derivatives of alkyl- oralkenyl-substituted succinic anhydride and especially the correspondingderivatives of polyisobutenylsuccinic anhydride which are obtainable byreacting conventional or high-reactivity polyisobutene havingM_(n)=preferably 300 to 5000, more preferably 300 to 3000, even morepreferably 500 to 2500, even more especially preferably 700 to 2500 andespecially 800 to 1500, with maleic anhydride by a thermal route in anene reaction or via the chlorinated polyisobutene. The moieties havinghydroxyl and/or amino and/or amido and/or imido groups are, for example,carboxylic acid groups, acid amides of monoamines, acid amides of di- orpolyamines which, in addition to the amide function, also have freeamine groups, succinic acid derivatives having an acid and an amidefunction, carboximides with monoamines, carboximides with di- orpolyamines which, in addition to the imide function, also have freeamine groups, or diimides which are formed by the reaction of di- orpolyamines with two succinic acid derivatives. In the presence of imidomoieties D(h), the further detergent additive in the context of thepresent invention is, however, used only up to a maximum of 100% of theweight of compounds with betaine structure. Such fuel additives arecommon knowledge and are described, for example, in documents (1) and(2). They are preferably the reaction products of alkyl- oralkenyl-substituted succinic acids or derivatives thereof with aminesand more preferably the reaction products of polyisobutenyl-substitutedsuccinic acids or derivatives thereof with amines. Of particularinterest in this context are reaction products with aliphatic polyamines(polyalkyleneimines) such as especially ethylenediamine,diethylenetriamine, triethylenetetramine, tetraethylenepentamine,pentaethylenehexamine and hexaethyleneheptamine, which have an imidestructure.

Additives comprising moieties (Di) obtained by Mannich reaction ofsubstituted phenols with aldehydes and mono- or polyamines arepreferably reaction products of polyisobutene-substituted phenols withformaldehyde and mono- or polyamines such as ethylenediamine,diethylenetriamine, triethylenetetramine, tetraethylenepentamine ordimethylaminopropylamine. The polyisobutenyl-substituted phenols maystem from conventional or high-reactivity polyisobutene having M_(n)=300to 5000. Such “polyisobutene Mannich bases” are described in particularin EP-A 831 141.

One or more of the detergent additives mentioned can be added to thefuel in such an amount that the dosage of these detergent additives ispreferably 25 to 2500 ppm by weight, especially 75 to 1500 ppm byweight, in particular 150 to 1000 ppm by weight.

B2) Carrier Oils

Carrier oils additionally used may be of mineral or synthetic nature.Suitable mineral carrier oils are the fractions obtained in crude oilprocessing, such as brightstock or base oils having viscosities, forexample, from the SN 500 to 2000 class; but also aromatic hydrocarbons,paraffinic hydrocarbons and alkoxyalkanols. Likewise useful is afraction which is obtained in the refining of mineral oil and is knownas “hydrocrack oil” (vacuum distillate cut having a boiling range fromabout 360 to 500° C., obtainable from natural mineral oil which has beencatalytically hydrogenated and isomerized under high pressure and alsodeparaffinized). Likewise suitable are mixtures of the abovementionedmineral carrier oils.

Examples of suitable synthetic carrier oils are polyolefins(polyalphaolefins or polyinternalolefins), (poly)esters,(poly)alkoxylates, polyethers, aliphatic polyetheramines,alkylphenol-started polyethers, alkylphenol-started polyetheramines andcarboxylic esters of long-chain alkanols.

Examples of suitable polyolefins are olefin polymers having M_(n)=400 to1800, in particular based on polybutene or polyisobutene (hydrogenatedor unhydrogenated).

Examples of suitable polyethers or polyetheramines are preferablycompounds comprising polyoxy-C₂- to C₄-alkylene moieties which areobtainable by reacting C₂- to C₆₀-alkanols, C₆- to C₃₀-alkanediols,mono- or di-C₂- to C₃₀-alkylamines, C₁- to C₃₀-alkylcyclohexanols or C₁-to C₃₀-alkylphenols with 1 to 30 mol of ethylene oxide and/or propyleneoxide and/or butylene oxide per hydroxyl group or amino group, and, inthe case of the polyetheramines, by subsequent reductive amination withammonia, monoamines or polyamines. Such products are described inparticular in EP-A 310 875, EP-A 356 725, EP-A 700 985 and U.S. Pat. No.4,877,416. For example, the polyetheramines used may be poly-C₂- toC₆-alkylene oxide amines or functional derivatives thereof. Typicalexamples thereof are tridecanol butoxylates or isotridecanolbutoxylates, isononylphenol butoxylates and also polyisobutenolbutoxylates and propoxylates, and also the corresponding reactionproducts with ammonia.

Examples of carboxylic esters of long-chain alkanols are in particularesters of mono-, di- or tricarboxylic acids with long-chain alkanols orpolyols, as described in particular in DE-A 38 38 918. The mono-, di- ortricarboxylic acids used may be aliphatic or aromatic acids; suitableester alcohols or polyols are in particular long-chain representativeshaving, for example, 6 to 24 carbon atoms. Typical representatives ofthe esters are adipates, phthalates, isophthalates, terephthalates andtrimellitates of isooctanol, isononanol, isodecanol and isotridecanol,for example di(n- or isotridecyl) phthalate.

Further suitable carrier oil systems are described, for example, in DE-A38 26 608, DE-A 41 42 241, DE-A 43 09 074, EP-A 452 328 and EP-A 548617.

Examples of particularly suitable synthetic carrier oils arealcohol-started polyethers having about 5 to 35, preferably about 5 to30, more preferably 10 to 30 and especially 15 to 30 C₃- to C₆-alkyleneoxide units, for example selected from propylene oxide, n-butylene oxideand isobutylene oxide units, or mixtures thereof, per alcohol molecule.Nonlimiting examples of suitable starter alcohols are long-chainalkanols or phenols substituted by long-chain alkyl in which thelong-chain alkyl radical is in particular a straight-chain or branchedC₆- to C₁₈-alkyl radical. Particular examples include tridecanol andnonylphenol. Particularly preferred alcohol-started polyethers are thereaction products (polyetherification products) of monohydric aliphaticC₆- to C₁₈-alcohols with C₃- to C₆-alkylene oxides. Examples ofmonohydric aliphatic C₆-C₁₈-alcohols are hexanol, heptanol, octanol,2-ethylhexanol, nonyl alcohol, decanol, 3-propylheptanol, undecanol,dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecanol,octadecanol and the constitutional and positional isomers thereof. Thealcohols can be used either in the form of the pure isomers or in theform of technical grade mixtures. A particularly preferred alcohol istridecanol. Examples of C₃- to C₆-alkylene oxides are propylene oxide,such as 1,2-propylene oxide, butylene oxide, such as 1,2-butylene oxide,2,3-butylene oxide, isobutylene oxide or tetrahydrofuran, pentyleneoxide and hexylene oxide. Particular preference among these is given toC₃- to C₄-alkylene oxides, i.e. propylene oxide such as 1,2-propyleneoxide and butylene oxide such as 1,2-butylene oxide, 2,3-butylene oxideand isobutylene oxide. Especially butylene oxide is used.

Further suitable synthetic carrier oils are alkoxylated alkylphenols, asdescribed in DE-A 10 102 913.

Particular carrier oils are synthetic carrier oils, particularpreference being given to the above-described alcohol-startedpolyethers.

The carrier oil or the mixture of different carrier oils is added to thefuel in an amount of preferably 1 to 1000 ppm by weight, more preferablyof 10 to 500 ppm by weight and especially of 20 to 100 ppm by weight.

B3) Cold Flow Improvers

Suitable cold flow improvers are in principle all organic compoundswhich are capable of improving the flow performance of middle distillatefuels or diesel fuels under cold conditions. For the intended purpose,they must have sufficient oil solubility. In particular, useful coldflow improvers for this purpose are the cold flow improvers (middledistillate flow improvers, MDFIs) typically used in the case of middledistillates of fossil origin, i.e. in the case of customary mineraldiesel fuels. However, it is also possible to use organic compoundswhich partly or predominantly have the properties of a wax antisettlingadditive (WASA) when used in customary diesel fuels. They can also actpartly or predominantly as nucleators. It is, though, also possible touse mixtures of organic compounds effective as MDFIs and/or effective asWASAs and/or effective as nucleators.

The cold flow improver is typically selected from

-   (K1) copolymers of a C₂- to C₄₀-olefin with at least one further    ethylenically unsaturated monomer;-   (K2) comb polymers;-   (K3) polyoxyalkylenes;-   (K4) polar nitrogen compounds;-   (K5) sulfocarboxylic acids or sulfonic acids or derivatives thereof;    and-   (K6) poly(meth)acrylic esters.

It is possible to use either mixtures of different representatives fromone of the particular classes (K1) to (K6) or mixtures ofrepresentatives from different classes (K1) to (K6).

Suitable C₂- to C₄₀-olefin monomers for the copolymers of class (K1)are, for example, those having 2 to 20 and especially 2 to 10 carbonatoms, and 1 to 3 and preferably 1 or 2 carbon-carbon double bonds,especially having one carbon-carbon double bond. In the latter case, thecarbon-carbon double bond may be arranged either terminally (α-olefins)or internally. However, preference is given to α-olefins, morepreferably α-olefins having 2 to 6 carbon atoms, for example propene,1-butene, 1-pentene, 1-hexene and in particular ethylene.

In the copolymers of class (K1), the at least one further ethylenicallyunsaturated monomer is preferably selected from alkenyl carboxylates,(meth)acrylic esters and further olefins.

When further olefins are also copolymerized, they are preferably higherin molecular weight than the abovementioned C₂- to C₄₀-olefin basemonomer. When, for example, the olefin base monomer used is ethylene orpropene, suitable further olefins are in particular C₁₀- toC₄₀-α-olefins. Further olefins are in most cases only additionallycopolymerized when monomers with carboxylic ester functions are alsoused.

Suitable (meth)acrylic esters are, for example, esters of (meth)acrylicacid with C₁- to C₂₀-alkanols, especially C₁- to C₁₀-alkanols, inparticular with methanol, ethanol, propanol, isopropanol, n-butanol,sec-butanol, isobutanol, tert-butanol, pentanol, hexanol, heptanol,octanol, 2-ethylhexanol, nonanol and decanol, and structural isomersthereof.

Suitable alkenyl carboxylates are, for example, C₂- to C₁₄-alkenylesters, for example the vinyl and propenyl esters, of carboxylic acidshaving 2 to 21 carbon atoms, whose hydrocarbon radical may be linear orbranched. Among these, preference is given to the vinyl esters. Amongthe carboxylic acids with a branched hydrocarbon radical, preference isgiven to those whose branch is in the α-position to the carboxyl group,the α-carbon atom more preferably being tertiary, i.e. the carboxylicacid being a so-called neocarboxylic acid. However, the hydrocarbonradical of the carboxylic acid is preferably linear.

Examples of suitable alkenyl carboxylates are vinyl acetate, vinylpropionate, vinyl butyrate, vinyl 2-ethylhexanoate, vinyl neopentanoate,vinyl hexanoate, vinyl neononanoate, vinyl neodecanoate and thecorresponding propenyl esters, preference being given to the vinylesters. A particularly preferred alkenyl carboxylate is vinyl acetate;typical copolymers of group (K1) resulting therefrom are ethylene-vinylacetate copolymers (“EVAs”), which are some of the most frequently used.Ethylene-vinyl acetate copolymers usable particularly advantageously andtheir preparation are described in WO 99/29748.

Suitable copolymers of class (K1) are also those which comprise two ormore different alkenyl carboxylates in copolymerized form, which differin the alkenyl function and/or in the carboxylic acid group. Likewisesuitable are copolymers which, as well as the alkenyl carboxylate(s),comprise at least one olefin and/or at least one (meth)acrylic ester incopolymerized form.

Terpolymers of a C₂- to C₄₀-α-olefin, a C₁- to C₂₀-alkyl ester of anethylenically unsaturated monocarboxylic acid having 3 to 15 carbonatoms and a C₂- to C₁₄-alkenyl ester of a saturated monocarboxylic acidhaving 2 to 21 carbon atoms are also suitable as copolymers of class(K1). Terpolymers of this kind are described in WO 2005/054314. Atypical terpolymer of this kind is formed from ethylene, 2-ethylhexylacrylate and vinyl acetate.

The at least one or the further ethylenically unsaturated monomer(s) arecopolymerized in the copolymers of class (K1) in an amount of preferably1 to 50% by weight, especially 10 to 45% by weight and in particular 20to 40% by weight, based on the overall copolymer. The main proportion interms of weight of the monomer units in the copolymers of class (K1)therefore originates generally from the C₂ to C₄₀ base olefins.

The copolymers of class (K1) preferably have a number-average molecularweight M_(n) of 1000 to 20 000, more preferably 1000 to 10 000 and inparticular 1000 to 8000.

Typical comb polymers of component (K2) are, for example, obtainable bythe copolymerization of maleic anhydride or fumaric acid with anotherethylenically unsaturated monomer, for example with an α-olefin or anunsaturated ester, such as vinyl acetate, and subsequent esterificationof the anhydride or acid function with an alcohol having at least 10carbon atoms. Further suitable comb polymers are copolymers of α-olefinsand esterified comonomers, for example esterified copolymers of styreneand maleic anhydride or esterified copolymers of styrene and fumaricacid. Suitable comb polymers may also be polyfumarates or polymaleates.Homo- and copolymers of vinyl ethers are also suitable comb polymers.Comb polymers suitable as components of class (K2) are, for example,also those described in WO 2004/035715 and in “Comb-Like Polymers.Structure and Properties”, N. A. Platé and V. P. Shibaev, J. Poly. Sci.Macromolecular Revs. 8, pages 117 to 253 (1974)”. Mixtures of combpolymers are also suitable.

Polyoxyalkylenes suitable as components of class (K3) are, for example,polyoxyalkylene esters, polyoxyalkylene ethers, mixed polyoxyalkyleneester/ethers and mixtures thereof. These polyoxyalkylene compoundspreferably comprise at least one linear alkyl group, preferably at leasttwo linear alkyl groups, each having 10 to 30 carbon atoms and apolyoxyalkylene group having a number-average molecular weight of up to5000. Such polyoxyalkylene compounds are described, for example, in EP-A061 895 and also in U.S. Pat. No. 4,491,455. Particular polyoxyalkylenecompounds are based on polyethylene glycols and polypropylene glycolshaving a number-average molecular weight of 100 to 5000. Additionallysuitable are polyoxyalkylene mono- and diesters of fatty acids having 10to 30 carbon atoms, such as stearic acid or behenic acid.

Polar nitrogen compounds suitable as components of class (K4) may beeither ionic or nonionic and preferably have at least one substituent,in particular at least two substituents, in the form of a tertiarynitrogen atom of the general formula >NR⁷ in which R⁷ is a C₈- toC₄₀-hydrocarbon radical. The nitrogen substituents may also bequaternized, i.e. be in cationic form. An example of such nitrogencompounds is that of ammonium salts and/or amides which are obtainableby the reaction of at least one amine substituted by at least onehydrocarbon radical with a carboxylic acid having 1 to 4 carboxyl groupsor with a suitable derivative thereof. The amines preferably comprise atleast one linear C₈- to C₄₀-alkyl radical. Primary amines suitable forpreparing the polar nitrogen compounds mentioned are, for example,octylamine, nonylamine, decylamine, undecylamine, dodecylamine,tetradecylamine and the higher linear homologs. Secondary aminessuitable for this purpose are, for example, dioctadecylamine andmethylbehenylamine. Also suitable for this purpose are amine mixtures,in particular amine mixtures obtainable on the industrial scale, such asfatty amines or hydrogenated tallamines, as described, for example, inUllmann's Encyclopedia of Industrial Chemistry, 6th Edition, “Amines,aliphatic” chapter. Acids suitable for the reaction are, for example,cyclohexane-1,2-dicarboxylic acid, cyclohexene-1,2-dicarboxylic acid,cyclopentane-1,2-dicarboxylic acid, naphthalenedicarboxylic acid,phthalic acid, isophthalic acid, terephthalic acid, and succinic acidssubstituted by long-chain hydrocarbon radicals.

In particular, the component of class (K4) is an oil-soluble reactionproduct of poly(C₂- to C₂₀-carboxylic acids) having at least onetertiary amino group with primary or secondary amines. The poly(C₂- toC₂₀-carboxylic acids) which have at least one tertiary amino group andform the basis of this reaction product comprise preferably at least 3carboxyl groups, especially 3 to 12 and in particular 3 to 5 carboxylgroups. The carboxylic acid units in the polycarboxylic acids havepreferably 2 to 10 carbon atoms, and are especially acetic acid units.The carboxylic acid units are suitably bonded to the polycarboxylicacids, usually via one or more carbon and/or nitrogen atoms. They arepreferably attached to tertiary nitrogen atoms which, in the case of aplurality of nitrogen atoms, are bonded via hydrocarbon chains.

The component of class (K4) is preferably an oil-soluble reactionproduct based on poly(C₂- to C₂₀-carboxylic acids) which have at leastone tertiary amino group and are of the general formula IIa or IIb

in which the variable A is a straight-chain or branched C₂- toC₆-alkylene group or the moiety of the formula III

and the variable B is a C₁- to C₁₉-alkylene group. The compounds of thegeneral formulae IIa and IIb especially have the properties of a WASA.

Moreover, the preferred oil-soluble reaction product of component (K4),especially that of the general formula IIa or IIb, is an amide, anamide-ammonium salt or an ammonium salt in which no, one or morecarboxylic acid groups have been converted to amide groups.

Straight-chain or branched C₂- to C₆-alkylene groups of the variable Aare, for example, 1,1-ethylene, 1,2-propylene, 1,3-propylene,1,2-butylene, 1,3-butylene, 1,4-butylene, 2-methyl-1,3-propylene,1,5-pentylene, 2-methyl-1,4-butylene, 2,2-dimethyl-1,3-propylene,1,6-hexylene (hexamethylene) and in particular 1,2-ethylene. Thevariable A comprises preferably 2 to 4 and especially 2 or 3 carbonatoms.

C₁- to C₁₉-alkylene groups of the variable B are, for example,1,2-ethylene, 1,3-propylene, 1,4-butylene, hexamethylene, octamethylene,decamethylene, dodecamethylene, tetradecamethylene, hexadecamethylene,octadecamethylene, nonadecamethylene and especially methylene. Thevariable B comprises preferably 1 to 10 and especially 1 to 4 carbonatoms.

The primary and secondary amines as a reaction partner for thepolycarboxylic acids to form component (K4) are typically monoamines,especially aliphatic monoamines. These primary and secondary amines maybe selected from a multitude of amines which bear hydrocarbon radicalswhich may optionally be bonded to one another.

These parent amines of the oil-soluble reaction products of component(K4) are usually secondary amines and have the general formula HN(R⁸)₂in which the two variables R⁸ are each independently straight-chain orbranched C₁₀- to C₃₀-alkyl radicals, especially C₁₄- to C₂₄-alkylradicals. These relatively long-chain alkyl radicals are preferablystraight-chain or only slightly branched. In general, the secondaryamines mentioned, with regard to their relatively long-chain alkylradicals, derive from naturally occurring fatty acid and fromderivatives thereof. The two R⁸ radicals are preferably identical.

The secondary amines mentioned may be bonded to the polycarboxylic acidsby means of amide structures or in the form of the ammonium salts; it isalso possible for only a portion to be present as amide structures andanother portion as ammonium salts. Preferably only few, if any, freeacid groups are present. The oil-soluble reaction products of component(K4) are preferably present completely in the form of the amidestructures.

Typical examples of such components (K4) are reaction products ofnitrilotriacetic acid, of ethylenediaminetetraacetic acid or ofpropylene-1,2-diaminetetraacetic acid with in each case 0.5 to 1.5 molper carboxyl group, especially 0.8 to 1.2 mol per carboxyl group, ofdioleylamine, dipalmitinamine, dicoconut fatty amine, distearylamine,dibehenylamine or especially ditallow fatty amine. A particularlypreferred component (K4) is the reaction product of 1 mol ofethylenediaminetetraacetic acid and 4 mol of hydrogenated ditallow fattyamine.

Further typical examples of component (K4) include theN,N-dialkylammonium salts of 2-N′,N′-dialkylamidobenzoates, for examplethe reaction product of 1 mol of phthalic anhydride and 2 mol ofditallow fatty amine, the latter being hydrogenated or unhydrogenated,and the reaction product of 1 mol of an alkenylspirobislactone with 2mol of a dialkylamine, for example ditallow fatty amine and/or tallowfatty amine, the last two being hydrogenated or unhydrogenated.

Further typical structure types for the component of class (K4) arecyclic compounds with tertiary amino groups or condensates of long-chainprimary or secondary amines with carboxylic acid-containing polymers, asdescribed in WO 93/18115.

Sulfocarboxylic acids, sulfonic acids or derivatives thereof which aresuitable as cold flow improvers of class (K5) are, for example, theoil-soluble carboxamides and carboxylic esters of ortho-sulfobenzoicacid, in which the sulfonic acid function is present as a sulfonate withalkyl-substituted ammonium cations, as described in EP-A 261 957.

Poly(meth)acrylic esters suitable as cold flow improvers of class (K6)are either homo- or copolymers of acrylic and methacrylic esters.Preference is given to copolymers of at least two different(meth)acrylic esters which differ with regard to the esterified alcohol.The copolymer optionally comprises another different olefinicallyunsaturated monomer in copolymerized form. The weight-average molecularweight of the polymer is preferably 50 000 to 500 000. A particularlypreferred polymer is a copolymer of methacrylic acid and methacrylicesters of saturated C₁₄ and C₁₅ alcohols, the acid groups having beenneutralized with hydrogenated tallamine. Suitable poly(meth)acrylicesters are described, for example, in WO 00/44857.

The cold flow improver or the mixture of different cold flow improversis added to the middle distillate fuel or diesel fuel in a total amountof preferably 10 to 5000 ppm by weight, more preferably of 20 to 2000ppm by weight, even more preferably of 50 to 1000 ppm by weight andespecially of 100 to 700 ppm by weight, for example of 200 to 500 ppm byweight.

B4) Lubricity Improvers

Suitable lubricity improvers or friction modifiers are based typicallyon fatty acids or fatty acid esters. Typical examples are tall oil fattyacid, as described, for example, in WO 98/004656, and glycerylmonooleate. The reaction products, described in U.S. Pat. No. 6,743,266B2, of natural or synthetic oils, for example triglycerides, andalkanolamines are also suitable as such lubricity improvers.

B5) Corrosion Inhibitors

Suitable corrosion inhibitors are, for example, succinic esters, inparticular with polyols, fatty acid derivatives, for example oleicesters, oligomerized fatty acids, substituted ethanolamines, andproducts sold under the trade name RC 4801 (Rhein Chemie Mannheim,Germany) or HiTEC 536 (Ethyl Corporation).

B6) Demulsifiers

Suitable demulsifiers are, for example, the alkali metal or alkalineearth metal salts of alkyl-substituted phenol- and naphthalenesulfonatesand the alkali metal or alkaline earth metal salts of fatty acids, andalso neutral compounds such as alcohol alkoxylates, e.g. alcoholethoxylates, phenol alkoxylates, e.g. tert-butylphenol ethoxylate ortert-pentylphenol ethoxylate, fatty acids, alkylphenols, condensationproducts of ethylene oxide (EO) and propylene oxide (PO), for exampleincluding in the form of EO/PO block copolymers, polyethyleneimines orelse polysiloxanes.

B7) Dehazers

Suitable dehazers are, for example, alkoxylated phenol-formaldehydecondensates, for example the products available under the trade namesNALCO 7D07 (Nalco) and TOLAD 2683 (Petrolite).

B8) Antifoams

Suitable antifoams are, for example, polyether-modified polysiloxanes,for example the products available under the trade names TEGOPREN 5851(Goldschmidt), Q 25907 (Dow Corning) and RHODOSIL (Rhone Poulenc).

B9) Cetane Number Improvers

Suitable cetane number improvers are, for example, aliphatic nitratessuch as 2-ethylhexyl nitrate and cyclohexyl nitrate and peroxides suchas di-tert-butyl peroxide.

B10) Antioxidants

Suitable antioxidants are, for example substituted phenols, such as2,6-di-tert-butylphenol and 6-di-tert-butyl-3-methylphenol, and alsophenylenediamines such as N,N′-di-sec-butyl-p-phenylenediamine.

B11) Metal Deactivators

Suitable metal deactivators are, for example, salicylic acid derivativessuch as N,N′-disalicylidene-1,2-propanediamine.

B12) Solvents

Suitable solvents are, for example, nonpolar organic solvents such asaromatic and aliphatic hydrocarbons, for example toluene, xylenes, whitespirit and products sold under the trade names SHELLSOL (RoyalDutch/Shell Group) and EXXSOL (ExxonMobil), and also polar organicsolvents, for example, alcohols such as 2-ethylhexanol, decanol andisotridecanol. Such solvents are usually added to the diesel fueltogether with the aforementioned additives and coadditives, which theyare intended to dissolve or dilute for better handling.

C) Fuels

The inventive additive is outstandingly suitable as a fuel additive andcan be used in principle in any fuels. It brings about a whole series ofadvantageous effects in the operation of internal combustion engineswith fuels. Preference is given to using the inventive quaternizedadditive in middle distillate fuels, especially diesel fuels.

The present invention therefore also provides fuels, especially middledistillate fuels, with a content of the inventive quaternized additivewhich is effective as an additive for achieving advantageous effects inthe operation of internal combustion engines, for example of dieselengines, especially of direct-injection diesel engines, in particular ofdiesel engines with common-rail injection systems. This effectivecontent (dosage) is generally 10 to 5000 ppm by weight, preferably 20 to1500 ppm by weight, especially 25 to 1000 ppm by weight, in particular30 to 750 ppm by weight, based in each case on the total amount of fuel.

Middle distillate fuels such as diesel fuels or heating oils arepreferably mineral oil raffinates which typically have a boiling rangefrom 100 to 400° C. These are usually distillates having a 95% point upto 360° C. or even higher. These may also be so-called “ultra low sulfurdiesel” or “city diesel”, characterized by a 95% point of, for example,not more than 345° C. and a sulfur content of not more than 0.005% byweight or by a 95% point of, for example, 285° C. and a sulfur contentof not more than 0.001% by weight. In addition to the mineral middledistillate fuels or diesel fuels obtainable by refining, thoseobtainable by coal gasification or gas liquefaction [“gas to liquid”(GTL) fuels] or by biomass liquefaction [“biomass to liquid” (BTL)fuels] are also suitable. Also suitable are mixtures of theaforementioned middle distillate fuels or diesel fuels with renewablefuels, such as biodiesel or bioethanol.

The qualities of the heating oils and diesel fuels are laid down indetail, for example, in DIN 51603 and EN 590 (cf. also Ullmann'sEncyclopedia of Industrial Chemistry, 5th edition, Volume A12, p. 617ff.).

In addition to the use thereof in the abovementioned middle distillatefuels of fossil, vegetable or animal origin, which are essentiallyhydrocarbon mixtures, the inventive quaternized additive can also beused in mixtures of such middle distillates with biofuel oils(biodiesel). Such mixtures are also encompassed by the term “middledistillate fuel” in the context of the present invention. They arecommercially available and usually comprise the biofuel oils in minoramounts, typically in amounts of 1 to 30% by weight, especially of 3 to10% by weight, based on the total amount of middle distillate of fossil,vegetable or animal origin and biofuel oil.

Biofuel oils are generally based on fatty acid esters, preferablyessentially on alkyl esters of fatty acids which derive from vegetableand/or animal oils and/or fats. Alkyl esters are typically understood tomean lower alkyl esters, especially C₁-C₄-alkyl esters, which areobtainable by transesterifying the glycerides which occur in vegetableand/or animal oils and/or fats, especially triglycerides, by means oflower alcohols, for example ethanol or in particular methanol (“FAME”).Typical lower alkyl esters based on vegetable and/or animal oils and/orfats, which find use as a biofuel oil or components thereof, are, forexample, sunflower methyl ester, palm oil methyl ester (“PME”), soya oilmethyl ester (“SME”) and especially rapeseed oil methyl ester (“RME”).

The middle distillate fuels or diesel fuels are more preferably thosehaving a low sulfur content, i.e. having a sulfur content of less than0.05% by weight, preferably of less than 0.02% by weight, moreparticularly of less than 0.005% by weight and especially of less than0.001% by weight of sulfur.

Useful gasoline fuels include all commercial gasoline fuel compositions.One typical representative which shall be mentioned here is theEurosuper base fuel to EN 228, which is customary on the market. Inaddition, gasoline fuel compositions of the specification according toWO 00/47698 are also possible fields of use for the present invention.

The inventive quaternized additive is especially suitable as a fueladditive in fuel compositions, especially in diesel fuels, forovercoming the problems outlined at the outset in direct-injectiondiesel engines, in particular in those with common-rail injectionsystems.

The invention is now illustrated in detail by the working examples whichfollow:

EXPERIMENTAL SECTION

A. General Test Methods

a) Determination of the Amide or Imide Content by IR Spectroscopy

The presence of amide or imide in a sample is examined by IRspectroscopy. The characteristic IR band for amide is at 1667±5 cm⁻¹,whereas the characteristic IR band of the imide is at 1705±5 cm⁻¹.

For this purpose, the samples were diluted 50% (m/m) in Solvesso andanalyzed in a 29 μm CaF₂ cuvette.

b) Engine Test

b1) XUD9 Test—Determination of Flow Restriction

The procedure was according to the standard stipulations of CECF-23-1-01.

b2) DW10 Test—Determination of Power Loss as a Result of InjectorDeposits in the Common-Rail Diesel Engine

To examine the influence of the additives on the performance ofdirect-injection diesel engines, the power loss was determined on thebasis of the official test method CEC F-098-08. The power loss is adirect measure of formation of deposits in the injectors.

A direct-injection diesel engine with common-rail system according totest method CEC F-098-08 was used. The fuel used was a commercial dieselfuel from Haltermann (RF-06-03). To synthetically induce the formationof deposits at the injectors, 1 ppm of zinc was added thereto in theform of a zinc didodecanoate solution. The results illustrate therelative power loss at 4000 rpm, measured during 12 hours of constantoperation. The value “t0” indicates the power loss normalized (100%) tothe value after 10 minutes; the value “t1” indicates the power lossnormalized to the value after one hour.

c) Brief Sedimentation Test (BS Test)—Determination of Action as a ColdFlow Improver

In the course of storage of diesel fuels in a storage or vehicle tank attemperatures below the cloud point (CP), precipitated paraffins cansettle out. The paraffin-rich bottom phase which forms has a relativelypoor cold performance, and can block filters of vehicles, thus leadingto collapse of the delivery rate.

The BS test simulates and visually evaluates possible sedimentation invehicle tanks. The CP and CFPP values of the diesel fuel phase enrichedwith paraffins obtained in the test are determined. The comparison ofthese values with those for the unsedimented fuel permits conclusionsabout the cold performance of the fuel. For this purpose, delta CP ordelta CFPP values are determined.

In the test, the optionally additized diesel fuel (DF) to be tested isprocessed at −13° C. for a total of 16 h. It is assessed visually.Subsequently, 80% by volume of upper phase of the fuel is sucked outcautiously from the top. After heating and homogenizing the remaining20% lower phase, the cloud point (CPCC) and the cold filter pluggingpoint (CFPPCC) thereof are determined with apparatus known per se.

The procedure is to filter the amounts of sample required through afluted filter (to DIN EN 116) to remove soil, coke constituents, wateror other undissolved impurities. The sample vessel (scaled measuringcylinder) is filled with 550 ml of sample liquid. If required, thesample is admixed with additive. It is heated to 50° C. in a water bath.The sample vessel is removed from the water bath and dried. The sampleis homogenized by inverting and shaking. The starting CP and CFPP values(“original”) of portions are determined. The sample temperature isadjusted to close to 25° C. by standing under air.

The sample vessel containing 500 ml of sample is suspended in a liquidbath by means of a holding device. Heat treatment begins at 25° C. Thesample is cooled to −13° C. within 2 h 40 min. The sample is stored at−13° C. for 13 h 20 min.

By means of a suction device, the sample is sucked out from the top downto a residual amount of 100 ml (20%). Sample movement and turbulenceshould be kept as low as possible. The sample vessel with the 20% lowerphase remaining therein is heated to 50° C. The lower phase ishomogenized and used to determine the final values of CP and CFPP (i.e.CPCC and CFPPCC).

d) Detection of the Betaine Structure

The betaine structure in inventive additives and the synthesisprecursors thereof is detected by determination of mass using MatrixAssisted Laser Desorption/Ionization-Time Of Flight Mass Spectrometry(MALDI-TOF-MS). The analysis is effected under the following conditions:

The BIFLEX 3 instrument from Bruker and a UV laser of wavelength 337 nmare used. The laser power is increased until the ionization threshold ofthe ions is attained. The matrix consists of 20 g/l of dithranol in THF(ion-exchanged), using a polymer concentration of approx. 2 g/I in THF.The procedure is as follows: the matrix is mixed with the particularpolymer in a ratio of 1:1, and 1 μl thereof is dried on the target(“dried-droplet technique”). The dried fractions are then dissolved in20 μl of the matrix solution and finally analyzed. A total of 100individual spectra are added up per measurement.

In addition, analysis is also effected by means of ESI-LC/MS(electrospray ionization liquid chromatography-mass spectrometry) in thesolvent THF. For this purpose, the LTQ/FT (Thermo) MS system and the LCsystem consisting of HP 1100 bin pump, HP 1100 ALS and HP 1100 DAD areused. Approx. 10 mg of test substance are dissolved in 1 ml of THF andanalyzed at room temperature. The resolution is 100 000.

e) Determination of the Motor Oil Compatibility of Diesel Fuels (DF)

The determination was effected by the methods in the catalog of criteriacompiled by the Deutsche Wissenschaftliche Gesellschaft für Erdöl,Erdgas and Kohle e.V. (DGMK) for the testing of lubricity additives indiesel fuels (DGMK Report 531)

In the fuel system of diesel vehicles, it is possible that small amountsof motor oil get into the diesel fuel circuit. In some cases, it hasbeen observed that reactions occurred between motor oil constituents andthe additives present in diesel fuels, and led to blockages of fuelfilters and hence to the failure of vehicles. Therefore, a test methodwas developed, with the aid of which reactions between motor oil anddiesel fuel additives which would lead to filter blockages arerecognized and assessed.

The additive to be tested is mixed with the same amount of thestipulated motor oil and conditioned at 90° C. over three days. Afterthis conditioning, the mixture is diluted with diesel fuel and mixed,and assessed with the aid of the SEDAB test (DGMK Report 531, appendixII-A). The results from both tests permit a statement about the “motoroil compatibility” of the diesel fuel additive to be tested.

Equipment and Test Media:

-   -   500 ml Erlenmeyer flask with NS19 ground glass stopper    -   alpha-methylnaphthalene    -   diesel fuel which passes the SEDAB test impeccably    -   motor oil (CEC Reference Lube RL-189, SAE 15W-40)

The DF provided for performance of the test and the motor oil should beassessed with the aid of the SEDAB test before the first use thereof.For this purpose, 10 g of motor oil are dissolved in 500 ml of DF. Toimprove the solubility, it may be necessary to add 10 ml ofalpha-methylnaphthalene and repeat the homogenization. This mixture isassessed immediately in the SEDAB test. When the mixture is filterableimpeccably, the DF can be used for the performance of the testing.

10 g of motor oil and 10 g of the additive to be tested are each weighedinto a 500 ml Erlenmeyer flask, and then homogenized by tilting theflask. In the case of poor miscibility, 10 ml of alpha-methylnaphthaleneare additionally added and the mixture is homogenized again. Thismixture is closed with a glass stopper and conditioned at a temperatureof 90° C. in a drying cabinet for three days.

After conditioning, the mixture is allowed to cool at room temperaturefor one hour and assessed visually for any deposits, turbidity, gelformation, etc. The mixture is made up to 500 ml with diesel fuel andmixed thoroughly. It is assessed visually. Should deposits have formed,they should be suspended by vigorous shaking before the performance ofthe SEDAB test. After standing for two hours, the mixture is assessedvisually again and then filtered through a 0.8 μm filter at a pressuredifferential of 800 mbar (see SEDAB test method). The total amount hasto be filterable within the fixed time.

In the case of occurrence of deposits, turbidity, gel formation and/orpoor filterability in the SEDAB test, the additive cannot be classifiedas motor oil-compatible. In the case of good filterability andimpeccable visual appearance, the additive can be classified as motoroil-compatible.

Specifications for the SEDAB Test:

500 ml of a pretreated DF are sucked through a membrane filter. The timein seconds needed for this volume to filter at 20±2° C. and 200 hPa(i.e. pressure differential approx. 800 hPa) is determined. When this ismore than two minutes, the amount of filtrate present after two minutesis noted.

Instruments/Materials Required

-   -   Membrane filter: from Sartorius, made of cellulose nitrate,        white, smooth, diameter 50 mm, pore size 0.8 μm.    -   Filtration apparatus: filtration unit with 500 ml funnel:        Sartorius SM 16 201    -   Suction bottle: capacity 1000 ml    -   Vacuum system: e.g. constant-vacuum TOM-VAC 1 Automatic        Zerosystem with a minimum pressure of 200 hPa.    -   Drying cabinet for heat treatment at 90±3° C., without air        circulation    -   Tweezers    -   Glass Petri dish, diameter approx. 125 mm, with acceptable lid    -   Sample vessel: measuring cylinder (capacity 500 ml) with glass        joint and stopper.

To prepare the sample, the sample vessel of the original fuel sample isshaken with 20 vertical strokes. The sample is left to stand at roomtemperature for 16 hours. Immediately before the measurement, the fuelis homogenized once again by shaking (10 strokes) and introduced intothe 500 ml funnel of the test apparatus.

The membrane filters are conditioned at 90±3° C. for a half hour in adrying cabinet and then stored in a desiccator until use. Thecorrespondingly prepared membrane filter is placed into the filtrationapparatus. The 500 ml funnel is filled with the entire sample (500 ml)and then a pressure of 200 hPa (absolute, corresponds to pressuredifferential approx. 800 hPa) is immediately applied. It should beensured that no fuel sample is poured in thereafter. The filtration timeis reported rounded to full seconds. If a filtration time of two minutesis exceeded without the entire sample being filtered, the test is endedand the volume of the fuel which has passed through to that point ismeasured. In this case, the result is reported as “>2 minutes” and theamount of sample (ml) filtered by the time the test was stopped. Whenthe filtration time of the sample is more than two minutes, acorresponding specimen should be heated to 50° C. for 30 minutes andthen filtered. If the test result is again above two minutes, the totalsoil content of the fuel should be determined to DIN 51 419.

After the filtration, funnel and filter are rinsed with n-heptane andthen with petroleum spirit (40/80) to free them of DF. The membranefilter is cautiously removed from the filter plate with tweezers, placedinto a clean Petri dish and dried in a drying cabinet at 90±3° C. withthe lid half-open for 30 minutes. Thereafter, the Petri dish is placedinto the desiccator for cooling for at least 15 minutes.

Samples which are filterable within two minutes by the above-describedprocess are classified as “uncritical” with regard to the present testmethod. Diesel fuels which are not filterable within this time should beclassified as “critical” and can lead to filter blockages in vehiclesand at filling stations. In the case of samples with critical behavior,the membrane filter should be studied optically (microscopically) or bymeans of infrared spectroscopy for the cause of the blockage.

B. Preparation and Analysis Examples

Reactants Used:

PIBSA: Mw=1100; hydrolysis number=85 mg KOH/g

DMAPA: Mw=102.18

Styrene oxide: Mw=120.15

Acetic acid: Mw=60.05

Preparation Example 1 Synthesis of an Inventive Acid-Free QuaternizedSuccinamide (PIBSA/DMAPA/Styrene Oxide; Amidation at 40° C.)

386.8 g (0.35 mol) of polyisobutenesuccinic anhydride (PIBSA 1000) aredissolved in 176 g of Solvesso 150 in a 2-liter four-necked flask atroom temperature under a gentle N₂ stream. After the addition of 29.9 g(0.29 mol) of 3-dimethylamino-1-propylamine (DMAPA), the reactiontemperature rises to 40° C. The solution is stirred at 40° C. for 10minutes. Subsequently, 34.2 g (0.29 mol) of (1,2-epoxyethyl)benzene areadded, which is followed by a further reaction time of 7 hours at 70° C.under N₂. The solution is finally adjusted to an active ingredientcontent of 50% with 274.9 g of Solvesso 150.

By IR analysis, it was possible to detect the formation of the inventiveamide addition product (A).

By means of ESI-LC/MS and MALDI-TOF-MS, the betaine structure of (A) wasdetermined experimentally.

Preparation Example 2(Comparison) Synthesis of an Acid-ContainingQuaternized Succinimide (PIBSA/DMAPA/Styrene Oxide/Acetic Acid)Analogously to WO 2006/135881

The overall experiment is performed under a gentle N₂ stream. Theinitial charge of PIBSA 1000 (481.61 g) and Pilot 900 oil (84.99 g) isstirred at 110° C. Then DMAPA (37.28 g) is metered in at 110-115° C.within 42 minutes. A slightly exothermic reaction is observed.Subsequently, the mixture is heated to 150° C. and stirred at 150° C.for 3 h to remove water of reaction. The mixture is then cooled to roomtemperature, and successively admixed with MeOH (152 g), acetic acid(21.91 g) and styrene oxide (43.84 g). The mixture is then stirred atreflux (67-69° C.) for 5 h. After standing at 30-35° C. overnight, themixture is concentrated by distillation (1 h/6 mbar/36° C. oil bath).The final weight of 661.1 g is adjusted to an active ingredient contentof 50% with Pilot 900 oil (493.07 g).

By IR analysis, it was possible to detect the formation of the imide(B).

By means of ESI-LC/MS and MALDI-TOF-MS, the absence of a betainestructure in (B) was demonstrated experimentally.

C. Use Examples

In the use examples which follow, the additives are used either as apure substance (as synthesized in the above preparation examples) or inthe form of an additive package. The following packages were used:

M2450: Inventive Additive Package

Additive Proportion (%) Product according 48.06 to Prep. Ex. 1 Dehazer0.92 Antifoam 1.11 Solvesso 150 25.88 Pilot 900 24.03 Sum 100

M2452: Comparative Additive Package

Additive Proportion (%) Product according 48.06 to Prep. Ex. 2 Dehazer0.92 Antifoam 1.11 Solvesso 150 49.91 Sum 100

Use Example 1 Determination of the Additive Action on the Formation ofDeposits in Diesel Engine Injection Nozzles

a) XUD9 Tests

Fuel used: RF-06-03 (reference diesel, Haltermann Products, Hamburg)

The results are compiled in the table which follows:

Active Flow restriction ingredient Active ingredient 0.1 mm needledosage dosage in the fuel stroke Ex. Designation [mg/kg] [mg/kg] [%] #1Blank value — — 61 #2 Additive according 60 30 4.2 to preparationexample 1

b) DW10 Test

The test results are shown in FIG. 1. The t0 values are plotted therein.

It is found that, at the same dosage (100 mg/kg of active ingredient,i.e. 200 ppm of preparation example 1), the inventive amide additive(rhombuses) and the imide comparative additive (triangles) significantlyreduce the power loss observed for unadditized fuel (squares), althoughthe inventive additive stabilizes the remaining power loss in the regionof about 0.5% over the entire test duration, i.e. 99.5% of the originalmaximum engine power is maintained. With the corresponding comparativeadditive, however, only a power of 98.5% of the original maximum enginepower is maintained.

Use Example 2 Determination of the Low-Temperature Properties—BriefSedimentation Test

Commercially available winter DF was additized in the manner specifiedin the table below with additive according to preparation example 1 (#3)and additive according to preparation example 2 (#2), and also withadditive package M2450 (#5) or M2452 (#4), and subjected to a BS test.The comparison (#1) used was DF with cold flow improver additive withoutamide and imide.

The test fuel used was diesel fuel from Bayernoil, (CP −6.5° C.).

All fuel samples (#1 to #5) were additionally additized with commercialmiddle distillate cold flow improver (MDFI) and wax antisettlingadditive (WASA).

It can be inferred from the test data compiled in the table whichfollows that the delta CP and CFPPCC values of the DFs additized inaccordance with the invention are significantly improved compared to theimide-containing DFs. The amide additization can thus significantlyimprove the cold performance of the DFs.

#1 #2 #3 #4 #5 — 130 ppm 130 ppm 270.5 ppm 270.5 ppm — M 2452 M 2450Comparison Invention Comparison Invention — (Prep. Ex. 2) (Prep. Ex. 1)(Prep. Ex. 2) (Prep. Ex. 1) CP CFPP CP CFPP CP CFPP CP CFPP CP CFPP −6.5−27 −27 −27 −27 −27 CPCC CFPPCC CPCC CFPPCC CPCC CFPPCC CPCC CFPPCC CPCCCFPPCC −3.3 −20 −3.8 −21 −6.2 −28 −1.8 −20 −6.1 −28 Delta CP — Delta CP— Delta CP — Delta CP — Delta CP — 3.2 — 2.7 — 0.3 — 4.7 — 0.4 — CFPP:CFPP of the overall fuel CFPPCC: CFPP of the lower phase CPCC: CP of thelower phase Delta CP: Difference from the CP of the fuel additized onlywith cold flow improver without addition of preparation example 1 or 2

Use Example 3 Determination of Motor Oil Compatibility

The determination was effected according to the specifications of DGMKReport 531.

Motor oil used: Wintershall 14W40 Multi Record Top

Diesel fuel (DF) used: RF-06-03 (reference diesel, Haltermann Products,Hamburg)

The additive to be tested is mixed with the same amount of mineral oil(10 g each time), conditioned at 90° C. for 3 days and assessed visuallyin the course thereof. Subsequently, the mixture is made up to 500 mlwith diesel fuel, mixed and assessed with the aid of the SEDABfiltration test (likewise defined in DGMK Report 531).

The results are compiled in the table which follows:

Product^(a)) Visual Solubility Test # (from preparation ex. X) 72 h/90°C. in DF Filtration 1 2 solid turbid, fail (comparison) (fail) insoluble2 1 liquid soluble pass (invention) (pass) ^(a))since both productscomprised different types of solvent (Solvesso 150 or Pilot 900) as aresult of the synthesis, they were admixed with the same amount of theother solvent in each case before performance of the test, so as to giveidentical test conditions.

Use Example 4 Determination of the Effect of IDIDs

The determination was effected in a passenger vehicle operating test.Commercial diesel fuel (DF) EN590 was additized (with customary DFadditives). The additive to be tested (inventive additive according topreparation example 1) was added to the EN590 DF. For comparison,commercial EN590 fuel which has not been admixed with an inventiveadditive was used. After the engine test had ended, the injectors werechecked for deposits. A surprisingly clear positive effect on IDIDs isobserved.

Test Procedure:

A passenger vehicle with common-rail injectors (magnet type), in whichinjector deposits had been found, was used for evaluation of theadditive for removal of these internal injector deposits.

The occurrence of brownish internal deposits in the injectors wasdetected by visual inspection of the solenoid coil face, of the valveplate in front of the face and of the valve seat face, and was alsonoticeable through rough and noisy engine running. It was likewisepossible to infer from the readout data that the amount of the fuelvolume injected into the cylinder deviated distinctly from the normalvalue.

The engine was first operated on the road with the tank filled withconventionally additized diesel without inventive additive, EN590 basefuel (50 liters, 750 km in mixed operation on freeways, other majorroads and downtown). No improvement in the internal deposits wasobserved when the vehicle was operated with a tank filled withunadditized fuel (cf. table below).

In the next step, the tank was filled with the same EN590 base fuel, butwhich had been admixed with the inventive additive in a dosage of 120mg/kg of active material. The car was run again for 750 km in mixedoperation. The deposits after 750 km were distinctly reduced after thistest operation with additized fuel, as was already detectable by softer,quieter engine operation. The readout data from the engine control unitalso showed that the amounts of fuel injected declined to the targetvalue.

After two tank fillings and operation over 1500 km with fuel additizedin accordance with the invention, the brownish injector deposits haddisappeared completely from the solenoid coil face, the valve plate infront of the face and the valve seat face, as was discernible visuallyafter the injector had been opened.

These results illustrate clearly that the inventive additive completelyremoved internal injector deposits (IDIDs) at low dosage. It canlikewise be concluded from the test results that the additive is alsocapable of preventing the formation of IDIDs even at low dosage rates.Furthermore, it was found that the inventive additive is capable ofeliminating not only wax- or soap-like IDIDs but also solid, carbon-likepolymeric deposits.

TABLE Test km Visual Test with inspection km additized Engine (solenoidcoil Data from Status total fuel running face) ECU Result Standard 0 0rough, severe injected severe vehicle for loud brownish fuel volumedeposits field deposits outside (carbon- operation target valuecontaining) 1st tank 750 0 rough, severe injected no filling + loudbrownish fuel volume improvement, running with deposits outside severeunadditized target value deposits fuel (EN590 (carbon- base fuel)containing) 1st tank 1500 750 quieter reduced injected reduced filling +deposits fuel volume deposits running with within additized target valuefuel (dosage 120 mg/kg) 2nd tank 2250 1500 gentle, deposits injecteddeposits filling + quiet completely fuel volume completely running withdisappeared within disappeared additized target value fuel (dosage 120mg/kg)

Reference is made explicitly to the disclosure of the publications citedherein.

The invention claimed is:
 1. A process for preparing a quaternizednitrogen compound, comprising: a) reacting a compound comprising atleast one oxygen- or nitrogen-containing group reactive with ananhydride and at least one quaternizable amino group with apolycarboxylic anhydride compound to obtain an amide compound having atleast one quaternizable amino group, and b) quaternizing the at leastone quaternizable amino group of the amide compound by reaction with ahydrocarbyl epoxide of formula (II) to obtain the quaternized nitrogencompound:

wherein the R^(a) radicals are each independently H or a hydrocarbylradical having 1 to 10 carbon atoms; wherein the plycarboxylic anhydridecompound is a di-, tri- or tetracarboxylic anhydride comprising ahydrophobic hydrocarbyl radical having a number-average molecular weight(M_(n)) of 85 to 20,000, and wherein at least the quaternizing isperformed in the absence of a protic solvent and a protic acid.
 2. Theprocess according to claim 1, wherein the quaternized nitrogen compoundis free of protic solvent and protic acid.
 3. The process according toclaim 1, wherein the quaternized nitrogen compound is a compoundrepresented by:

wherein n is a value such that the M_(n) of the polyisobutene chain isfrom 550 to 2300.